#include<cstdio>
#include<cstdint>

#include<array>
#include<utility>
#include<initializer_list>
#include<limits>

#include<string>
#include<vector>
#include<queue>

/**
 * Author: Cracker
 * Version: 0x02
*/
namespace Default_Source{
#ifndef _linux_
#define likely(x) __builtin_expect(!!(x),1)
#define unlikely(x) __builtin_expect(!!(x),0)
#endif
	namespace{
		template<typename T>
		constexpr T Inf{std::numeric_limits<T>::max()};
		template<typename T>
		constexpr T abs(const T&x){return x<T(0)?-x:x;}
		template<typename T>
		constexpr const T&min(const T&lhs,const T&rhs){return lhs<rhs?lhs:rhs;}
		template<typename T>
		constexpr T min(const std::initializer_list<T>&L){
			T ret=*L.begin();
			for(const T&it:L) ret=min(ret,it);
			return ret;
		}
		template<typename T>
		constexpr const T&max(const T&lhs,const T&rhs){return lhs<rhs?rhs:lhs;}
		template<typename T>
		constexpr T max(const std::initializer_list<T>&L){
			T ret=*L.begin();
			for(const T&it:L) ret=max(ret,it);
			return ret;
		}
		template<typename T>
		constexpr void swap(T&x,T&y){
			T tmp=std::move(x);
			x=std::move(y),y=std::move(tmp);
		}
	}
	namespace Bit{
		template<typename T>
		typename std::enable_if<std::is_signed<T>::value,T>::type bswap(T value){
			size_t n{(sizeof(T)<<3)-1};
			T ret{};
			for(size_t i=0,j=n-1;i<n;++i,--j) if((value>>i)&1) ret|=1<<j;
			return ret;
		}
		template<typename T>
		typename std::enable_if<std::is_unsigned<T>::value,T>::type bswap(T value){
			size_t n{sizeof(T)<<3};
			T ret{};
			for(size_t i=0,j=n-1;i<n;++i,--j) if((value>>i)&1) ret|=1<<j;
			return ret;
		}
	}
	namespace IO{
		namespace Flush{
			struct Input_Flush_Base{char getc(){return getchar();}};
			template<size_t BUFSIZE>
			class Fast_Input_Flush_Base{
			protected:
				char buf[BUFSIZE],*cur=buf;
			public:
				Fast_Input_Flush_Base(){std::fread(buf,1,BUFSIZE,stdin);}
				char getc(){return*cur++;}
			};
			template<size_t BUFSIZE>
			class Fast_Input_Flush_Safer{
			protected:
				char buf[BUFSIZE],*cur,*nil;
				bool reload(){return (nil=(cur=buf)+std::fread(buf,1,BUFSIZE,stdin))!=buf;}
			public:
				Fast_Input_Flush_Safer(){reload();}
				char getc(){return (cur!=nil||reload())?*cur++:EOF;}
			};
			struct Output_Flush_Base{void putc(char ch){putchar(ch);}};
			template<size_t BUFSIZE>
			class Fast_Output_Flush_Base{
				char buf[BUFSIZE],*cur=buf;
			public:
				~Fast_Output_Flush_Base(){std::fwrite(buf,1,cur-buf,stdout);}
				void putc(char ch){*cur++=ch;}
			};
			template<size_t BUFSIZE>
			class Fast_Output_Flush_Safer{
				char buf[BUFSIZE],*cur=buf;
				bool freeze(){return likely(cur!=buf)&&(fwrite(buf,1,cur-buf,stdout),cur=buf);}
			public:
				~Fast_Output_Flush_Safer(){freeze();}
				void putc(char ch){cur-buf==BUFSIZE&&freeze(),*cur++=ch;}
			};
		}
		template<typename _Input_Flush=Flush::Input_Flush_Base>
		class InStream{
			static _Input_Flush Input;
		public:
			template<typename T>
			typename std::enable_if<std::is_integral<T>::value,InStream>::type&operator>>(T&x){
				x=0;bool sign=false;char Ch=Input.getc();
				for(;!isdigit(Ch);Ch=Input.getc()) if(Ch=='-') sign=true;
				for(;isdigit(Ch);Ch=Input.getc()) x=x*10+(sign?-(Ch&15):(Ch&15));
				return *this;
			}
			InStream&operator>>(char*str){
				while(isspace(*str=Input.getc()));
				while(!isspace(*++str=Input.getc()));
				return *str='\0',*this;
			}
			template<typename ...Args>
			InStream&read(Args&&...args){return std::initializer_list<InStream>{*this>>args...},*this;}
			template<typename T>
			T read(){
				static T x;
				return read(x),x;
			}
		};
		template<typename _Input_Flush>
		_Input_Flush InStream<_Input_Flush>::Input;
		template<typename _Output_Flush=Flush::Output_Flush_Base>
		class OutStream{
			static _Output_Flush Output;
		public:
			template<typename T>
			typename std::enable_if<std::is_integral<T>::value,OutStream>::type&operator<<(T x){
				static char sta[114];
				int top=0;
				if(x<0){
					Output.putc('-');
					do sta[top++]=(-(x%10))|48,x/=10;
					while(x);
				}
				else
					do sta[top++]=(x%10)|48,x/=10;
					while(x);
				while(top) Output.putc(sta[--top]);
				return *this;
			}
			OutStream&operator<<(char Ch){return Output.putc(Ch),*this;}
			OutStream&operator<<(const char*Str){while(*Str) Output.putc(*Str++);return *this;}
			OutStream&operator<<(char*Str){return *this<<(static_cast<const char*>(Str));}
			template<typename ...Args>
			OutStream&write(Args...args){return std::initializer_list<OutStream>{*this<<args...},*this;}
			template<typename ...Args>
			OutStream&writeln(Args...args){return write(args...),Output.putc('\n'),*this;}
		};
		template<typename _Output_Flush>
		_Output_Flush OutStream<_Output_Flush>::Output;
	}
	namespace ModTool{
		template<typename _Tp,_Tp mod,_Tp phi=mod-1>
		struct Moder{
			static_assert(std::is_integral<_Tp>::value,"Only integers can be modulus.");
			template<typename T>
			constexpr _Tp norm(T x)const{return x<0?x%mod+mod:x%mod;}
			template<typename T>
			constexpr _Tp unorm(T x)const{return x%mod;}
			template<typename T,typename...Args>
			constexpr void plus(T&x,Args...args)const{x=norm(x),void(std::initializer_list<T>{(x=unorm(x+norm(args)))...});}
			template<typename T,typename...Args>
			constexpr void mult(T&x,Args...args)const{x=norm(x),void(std::initializer_list<T>{(x=unorm(x*norm(args)))...});}
			template<typename...Args>
			constexpr _Tp sum(Args...args)const{
				_Tp ret{0};
				return plus(ret,args...),ret;
			}
			template<typename...Args>
			constexpr _Tp prod(Args...args)const{
				_Tp ret{1};
				return mult(ret,args...),ret;
			}
			template<typename T>
			constexpr _Tp qpow(_Tp x,T pw)const{
				_Tp ret{1};
				x=norm(x);
				for(;pw;pw>>=1,x=unorm(x*x)) if(pw&1) ret=unorm(ret*x);
				return ret;
			}
			constexpr _Tp inv(_Tp x)const{return qpow(x,phi-1);}
			template<size_t N>
			constexpr auto getFac(){
				std::array<_Tp,N> Fac{};
				Fac[0]=1;
				for(size_t i=1;i<N;++i) Fac[i]=unorm(Fac[i-1]*i);
				return Fac;
			}
			template<size_t N>
			constexpr auto getInv(_Tp Fac){
				std::array<_Tp,N> Inv{};
				Inv[N-1]=inv(Fac),Inv[0]=1;
				for(size_t i=N-2;i;--i) Inv[i]=unorm(Inv[i+1]*(i+1));
				return Inv;
			}
		};
	}
	namespace DS{
		namespace Sgt{
			enum SegmentTree_Type{Single=1,Interval=2};
			template<typename Info,SegmentTree_Type _Modify,SegmentTree_Type _Query,typename Vec=std::vector<Info>>
			class SegmentTree{};
			template<typename Info,typename Vec>
			class SegmentTree<Info,Interval,Interval,Vec>{
			private:
				int st,ed;
				Vec tr;
				void build(int p,int l,int r){
					tr[p]={};
					if(l==r) return tr[p].init(l);
					int mid=(l+r)>>1;
					build(p<<1,l,mid),build(p<<1|1,mid+1,r);
					tr[p].pull(tr[p<<1],tr[p<<1|1]);
				}
				void modify(int p,int l,int r,int L,int R,const Info&V){
					if(L<=l&&r<=R) return tr[p].get(V);
					int mid=(l+r)>>1;
					tr[p].push(tr[p<<1],tr[p<<1|1]);
					if(L<=mid) modify(p<<1,l,mid,L,R,V);
					if(R>mid) modify(p<<1|1,mid+1,r,L,R,V);
					tr[p].pull(tr[p<<1],tr[p<<1|1]);
				}
				Info query(int p,int l,int r,int L,int R){
					if(L<=l&&r<=R) return tr[p];
					int mid=(l+r)>>1;
					tr[p].push(tr[p<<1],tr[p<<1|1]);
					if(L<=mid&&R>mid) return merge(query(p<<1,l,mid,L,R),query(p<<1|1,mid+1,r,L,R));
					else return L<=mid?query(p<<1,l,mid,L,R):query(p<<1|1,mid+1,r,L,R);
				}
			public:
				SegmentTree():st{},ed{},tr{}{}
				SegmentTree(int _st,int _ed):st{_st},ed{_ed}{tr.resize((ed-st+1)<<2);}
				void build(){build(1,st,ed);}
				void resize(int _st,int _ed){st=_st,ed=_ed,tr.resize((ed-st+1)<<2);}
				void modify(int L,int R,const Info&V){modify(1,st,ed,L,R,V);}
				Info query(int L,int R){return query(1,st,ed,L,R);}
				void modify(int X,const Info&V){modify(1,st,ed,X,X,V);}
				Info query(int X){return query(1,st,ed,X,X);}
			};
		}
	}
	namespace NetFlow{
		template<typename _Cap,template<typename...> typename _Vec=std::vector>
		class Maxi_Flow{
			struct edge{int ver,nxt;_Cap cap;};
			_Vec<int> Head;
			_Vec<edge> Edge;
		public:
			using edge_type=edge;
			using edge_point=int;
			edge_point edgeEnd()const{return -1;}
			edge_point edgeRev(edge_point e)const{return e^1;}
			Maxi_Flow():Head{},Edge{},Dep{}{}
			Maxi_Flow(int n):Edge{}{Head.resize(n,-1),Dep.resize(n),Que.resize(n);}
			Maxi_Flow(int n,int m){Head.resize(n,-1),Edge.reserve(m<<1),Dep.resize(n),Que.resize(n);}
			void clear(){std::fill(Head.begin(),Head.end(),-1),Edge.clear();}
			void resize(int n){Head.clear(),Head.resize(n,-1),Dep.resize(n),Que.resize(n);}
			void resize(int n,int m){Head.clear(),Head.resize(n,-1),Edge.reserve(m<<1),Dep.resize(n),Que.resize(n);}
			edge_point add(int u,int v,_Cap c){return Edge.push_back({v,Head[u],c}),Head[u]=Edge.size()-1;}
			edge_point link(int u,int v,_Cap c){return add(v,u,0),add(u,v,c);}
			const edge_point&getHead(int u)const{return Head[u];}
			const edge_type&getEdge(edge_point e)const{return Edge[e];}
			edge_type&cgEdge(edge_point e){return Edge[e];}
		private:
			_Vec<int> Dep,Cur,Que;
			bool bfs(int s,int t){
				std::fill(Dep.begin(),Dep.end(),-1);
				Que.resize(Head.size());
				static int head,tail;
				Dep[Que[head=tail=0]=s]=0;
				for(int u;head<=tail;) for(int e=Head[u=Que[head++]];~e;e=Edge[e].nxt)
					if(Edge[e].cap&&!~Dep[Edge[e].ver]) Dep[Que[++tail]=Edge[e].ver]=Dep[u]+1;
				return Dep[t]!=-1;
			}
			_Cap dfs(int u,int t,_Cap flow){
				if(u==t) return flow;
				_Cap rest=flow;
				for(int&e=Cur[u];~e&&rest;e=Edge[e].nxt)
					if(Edge[e].cap&&Dep[Edge[e].ver]==Dep[u]+1){
						_Cap cap=dfs(Edge[e].ver,t,min(rest,Edge[e].cap));
						if(cap!=0) Edge[e].cap-=cap,Edge[edgeRev(e)].cap+=cap,rest-=cap;
						else Dep[Edge[e].ver]=-1;
					}
				return flow-rest;
			}
		public:
			void output(){for(auto i=0u;i<Head.size();++i) for(int e=Head[i];~e;e=Edge[e].nxt) if(Edge[e].cap) printf("%d %d %d\n",i,Edge[e].ver,Edge[e].cap);}
			_Cap flow(int s,int t,_Cap limit=Inf<_Cap>){
				_Cap flow{};
				while(limit&&bfs(s,t)) for(Cur=Head;_Cap cap=dfs(s,t,limit);) flow+=cap,limit-=cap;
				return flow;
			}
		};
		template<typename _Cap,typename _Cost,template<typename...> typename _Vec=std::vector,template<typename...> typename _Que=std::queue>
		class Mini_Cost_Maxi_Flow{
			struct edge{int ver,nxt;_Cap cap;_Cost cost;};
			_Vec<int> Head;
			_Vec<edge> Edge;
		public:
			using edge_type=edge;
			using edge_point=int;
			edge_point edgeEnd()const{return -1;}
			edge_point edgeRev(edge_point e)const{return e^1;}
			Mini_Cost_Maxi_Flow():Head{},Edge{}{}
			Mini_Cost_Maxi_Flow(int n):Edge{}{Head.resize(n,-1),Dis.resize(n),Inq.resize(n);}
			Mini_Cost_Maxi_Flow(int n,int m){Head.resize(n,-1),Edge.reserve(m<<1),Dis.resize(n),Inq.resize(n);}
			void clear(){std::fill(Head.begin(),Head.end(),-1),Edge.clear();}
			void resize(int n){Head.clear(),Head.resize(n,-1),Dis.resize(n),Inq.resize(n);}
			void resize(int n,int m){Head.clear(),Head.resize(n,-1),Edge.reserve(m<<1),Dis.resize(n),Inq.resize(n);}
			edge_point add(int u,int v,_Cap c,_Cost w){return Edge.push_back({v,Head[u],c,w}),Head[u]=Edge.size()-1;}
			edge_point link(int u,int v,_Cap c,_Cost w){return add(v,u,0,-w),add(u,v,c,w);}
			const edge_point&getHead(int u)const{return Head[u];}
			const edge_type&getEdge(edge_point e)const{return Edge[e];}
		private:
			_Vec<int> Cur,Inq;
			_Vec<_Cost> Dis;
			bool spfa(int s,int t){
				std::fill(Dis.begin(),Dis.end(),Inf<_Cost>);
				std::fill(Inq.begin(),Inq.end(),0);
				static _Que<int> q;
				q.emplace(s),Dis[s]=0,Inq[s]=1;
				for(int u;!q.empty();){
					Inq[u=q.front()]=0,q.pop();
					for(int e=Head[u];~e;e=Edge[e].nxt)
						if(Edge[e].cap&&Dis[Edge[e].ver]>Dis[u]+Edge[e].cost)
							if(Dis[Edge[e].ver]=Dis[u]+Edge[e].cost,!Inq[Edge[e].ver]) q.emplace(Edge[e].ver),Inq[Edge[e].ver]=1;
				}
				return Dis[t]!=Inf<_Cost>;
			}
			_Cap dfs(int u,int t,_Cap flow){
				if(u==t) return flow;
				_Cap rest=flow;
				Inq[u]=1;
				for(int&e=Cur[u];~e&&rest;e=Edge[e].nxt)
					if(Edge[e].cap&&!Inq[Edge[e].ver]&&Dis[Edge[e].ver]==Dis[u]+Edge[e].cost){
						_Cap cap=dfs(Edge[e].ver,t,min(rest,Edge[e].cap));
						if(cap!=0) Edge[e].cap-=cap,Edge[edgeRev(e)].cap+=cap,rest-=cap;
						else Dis[Edge[e].ver]=Inf<_Cost>;
					}
				Inq[0]=1;
				return flow-rest;
			}
		public:
			void output(){for(auto i=0u;i<Head.size();++i) for(int e=Head[i];~e;e=Edge[e].nxt) if(Edge[e].cap) printf("%d %d %d\n",i,Edge[e].ver,Edge[e].cap);}
			std::pair<_Cap,_Cost> flow(int s,int t,_Cap limit=Inf<_Cap>){
				_Cap flow{};
				_Cost cost{};
				while(limit&&spfa(s,t)) for(Cur=Head;_Cap cap=dfs(s,t,limit);) flow+=cap,limit-=cap,cost+=cap*Dis[t];
				return {flow,cost};
			}
		};
	}
	namespace Mat{
		template<typename T>
		class Matrix{
		protected:
			int n,m;
			int**v;
			void Alloca(){
				if(n>0&&m>0){
					v=new int*[n]{};
					for(int i=0;i<n;++i) v[i]=new int[m]{};
				}
				else v=nullptr,n=m=0;
			}
			void Freeze(){
				if(n>0&&m>0){
					for(int i=0;i<n;++i) delete[] v[i];
					delete[] v;
				}
				v=nullptr,n=m=0;
			}
			void clone(int**p){for(int i=0;i<n;++i) for(int j=0;j<m;++j) v[i][j]=p[i][j];}
		public:
			int row()const{return n;}
			int col()const{return m;}
			Matrix():n{},m{},v{}{}
			Matrix(int _n,int _m):n{_n},m{_m},v{}{Alloca();}
			Matrix(int _n):n{_n},m{_n},v{}{Alloca(),init();}
			Matrix(const Matrix&it):n{it.n},m{it.m}{Alloca(),clone(it.v);}
			Matrix(Matrix&&it):Matrix{}{swap(n,it.n),swap(m,it.m),swap(v,it.v);}
			Matrix&operator=(const Matrix&it){return resize(it.n,it.m),clone(it.v),*this;}
			Matrix&operator=(Matrix&&it){return swap(n,it.n),swap(m,it.m),swap(v,it.v),*this;}
			void resize(int _n,int _m,int _v={}){
				Freeze(),n=_n,m=_m,Alloca();
				for(int i=0;i<n;++i) for(int j=0;j<m;++j) v[i][j]=_v;
			}
			T*operator[](int x){return v[x];}
			const T*operator[](int x)const{return v[x];}
			void init(){for(int i=0;i<n;++i) (*this)[i][i]=1;}
			~Matrix(){Freeze();}
			template<typename U>
			operator Matrix<U>()const{
				Matrix<U> ret(n,m);
				return ret.Alloca(),ret.clone(v),ret;
			}
		};
		template<typename Flush,typename T>
		IO::OutStream<Flush>&operator<<(IO::OutStream<Flush>&os,const Matrix<T>&it){
			for(int i=0;i<it.row();++i,os<<'\n') for(int j=0;j<it.col();++j) os<<it[i][j]<<' ';
			return os;
		}
	}
}
using namespace Default_Source;

/**
*/

constexpr int N=200;

IO::InStream<> Input;
IO::OutStream<> Output;

int n,a[N+1][N+1];
std::pair<int,int> id[N+1][N+1];
template<typename Flush>
IO::OutStream<Flush>&operator<<(IO::OutStream<Flush>&os,std::pair<int,int> p){return os<<p.first<<' '<<p.second;}
void print(){
	Output.writeln(n*(n-1)>>1);
	for(int i=1;i<=n;++i) for(int j=1;j<i;++j)
		Output<<id[i][j]<<' '<<id[j][i]<<'\n';
}
NetFlow::Maxi_Flow<int> G;

signed main(){

	for(int Test=Input.read<int>();Test;--Test){
		Input.read(n);
		for(int i=1;i<=n;++i) for(int j=1;j<=n;++j) Input.read(a[i][j]),id[i][j]={i,j};
		int s=0,t=(n<<1)+1;
		G.resize(t+1);
		for(int T=1;T<=n;++T){
			G.clear();
			for(int i=1;i<=n;++i) G.link(s,i,1),G.link(i+n,t,1);
			static int c[N+1][N+1];
			__builtin_memset(c,0,sizeof(c));
			for(int i=1;i<=n;++i) for(int j=1;j<=n;++j) if(!c[i][a[i][j]]) c[i][a[i][j]]=j,G.link(i,a[i][j]+n,1);
			// G.output();
			// Output.writeln();
			if(G.flow(s,t)!=n) return 0;
			for(int i=1;i<=n;++i) for(int e=G.getHead(i);e!=G.edgeEnd();e=G.getEdge(e).nxt)
				if(!G.getEdge(e).cap){
					int k=c[i][G.getEdge(e).ver-n];
					swap(id[i][k],id[i][T]),swap(a[i][k],a[i][T]);
				}
		}
		print();
	}

	return 0;
}