// what is matter? never mind. 
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,sse4,popcnt,abm,mmx,avx,avx2") 
#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rep(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
#define int long long
#define ull unsigned long long
#define SZ(x) ((int)((x).size()))
#define ALL(x) (x).begin(),(x).end()
using namespace std;
inline int read()
{
    char c=getchar();int x=0;bool f=0;
    for(;!isdigit(c);c=getchar())f^=!(c^45);
    for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
    if(f)x=-x;return x;
}

#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int,int>pii;
typedef vector<int>vi;

#define maxn 500006
#define inf 0x3f3f3f3f

int n,up;
int a[505][505],b[505][505];

struct edge{
	int u,v,w;
};

int fa[maxn];
int gf(int x){
	while(x!=fa[x])x=fa[x]=fa[fa[x]];
	return x;
}

vector<edge> mst(vector<edge>es){
	For(i,1,n) fa[i]=i;
	sort(es.begin(),es.end(),[&](auto a,auto b){
		return a.w>b.w;
	});
	vector<edge>res;
	for(auto [u,v,w]:es){
		if(gf(u)!=gf(v)){
			fa[gf(u)]=gf(v);
			res.pb({u,v,w});
		}
	}
	return res;
}

signed main()
{
	n=read(),up=read();
	For(i,1,n)For(j,1,i-1)a[i][j]=a[j][i]=read();
	For(i,1,n)For(j,1,i-1)b[i][j]=b[j][i]=read();
	For(i,1,n)For(j,i+1,n)
		For(k,1,n)if(k!=i&&k!=j){
			if(min(a[i][k],a[k][j])>a[i][j]){
				puts("NO");
				exit(0);
			}
			if(min(b[i][k],b[k][j])>b[i][j]){
				puts("NO");
				exit(0);
			}
		}
	
	vector<edge>es,resa,resb;
	For(i,1,n)For(j,i+1,n) if(a[i][j]+b[i][j]>=up) es.pb({i,j,a[i][j]});
	resa=mst(es);
	es.clear();
	For(i,1,n)For(j,i+1,n) if(a[i][j]+b[i][j]>=up) es.pb({i,j,b[i][j]});
	resb=mst(es);
	if(resa.size()!=n-1) puts("NO"),exit(0);
	cout<<resa.size()+resb.size()<<"\n";
	for(auto [u,v,w]:resa) cout<<u-1<<" "<<v-1<<" "<<up-w<<"\n";
	for(auto [u,v,w]:resb) cout<<u-1<<" "<<v-1<<" "<<w<<"\n";
	return 0;
}
/*

*/