#if defined(LOCAL) or not defined(LUOGU)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast,unroll-loops")
#endif
#include<bits/stdc++.h>
using namespace std;
struct time_helper
{
#ifdef LOCAL
	clock_t time_last;
#endif
	time_helper()
	{
#ifdef LOCAL
		time_last=clock();
#endif
	}
	void test()
	{
#ifdef LOCAL
		auto time_now=clock();
		std::cerr<<"time:"<<1.*(time_now-time_last)/CLOCKS_PER_SEC<<";all_time:"<<1.*time_now/CLOCKS_PER_SEC<<std::endl;
		time_last=time_now;
#endif
	}
	~time_helper()
	{
		test();
	}
}time_helper;
#ifdef LOCAL
#include"dbg.h"
#else
#define dbg(...) (__VA_ARGS__)
#endif
namespace Fread{const int SIZE=1<<16;char buf[SIZE],*S,*T;inline char getchar(){if(S==T){T=(S=buf)+fread(buf,1,SIZE,stdin);if(S==T)return'\n';}return *S++;}}namespace Fwrite{const int SIZE=1<<16;char buf[SIZE],*S=buf,*T=buf+SIZE;inline void flush(){fwrite(buf,1,S-buf,stdout);S=buf;}inline void putchar(char c){*S++=c;if(S==T)flush();}struct NTR{~NTR(){flush();}}ztr;}
#define getchar Fread::getchar
#define putchar Fwrite::putchar
#define Setprecision 10
#define between '\n'
#define __int128 long long
template<typename T>struct is_char{static constexpr bool value=(std::is_same<T,char>::value||std::is_same<T,signed char>::value||std::is_same<T,unsigned char>::value);};template<typename T>struct is_integral_ex{static constexpr bool value=(std::is_integral<T>::value||std::is_same<T,__int128>::value)&&!is_char<T>::value;};template<typename T>struct is_floating_point_ex{static constexpr bool value=std::is_floating_point<T>::value||std::is_same<T,__float128>::value;};namespace Fastio{struct Reader{template<typename T>typename std::enable_if_t<std::is_class<T>::value,Reader&>operator>>(T&x){for(auto &y:x)*this>>y;return *this;}template<typename T>typename std::enable_if_t<is_integral_ex<T>::value,Reader&>operator>>(T&x){char c=getchar();short f=1;while(c<'0'||c>'9'){if(c=='-')f*=-1;c=getchar();}x=0;while(c>='0'&&c<='9'){x=(x<<1)+(x<<3)+(c^48);c=getchar();}x*=f;return *this;}template<typename T>typename std::enable_if_t<is_floating_point_ex<T>::value,Reader&>operator>>(T&x){char c=getchar();short f=1,s=0;x=0;T t=0;while((c<'0'||c>'9')&&c!='.'){if(c=='-')f*=-1;c=getchar();}while(c>='0'&&c<='9'&&c!='.')x=x*10+(c^48),c=getchar();if(c=='.')c=getchar();else return x*=f,*this;while(c>='0'&&c<='9')t=t*10+(c^48),s++,c=getchar();while(s--)t/=10.0;x=(x+t)*f;return*this;}template<typename T>typename std::enable_if_t<is_char<T>::value,Reader&>operator>>(T&c){c=getchar();while(c=='\n'||c==' '||c=='\r')c=getchar();return *this;}Reader&operator>>(char*str){int len=0;char c=getchar();while(c=='\n'||c==' '||c=='\r')c=getchar();while(c!='\n'&&c!=' '&&c!='\r')str[len++]=c,c=getchar();str[len]='\0';return*this;}Reader&operator>>(std::string&str){str.clear();char c=getchar();while(c=='\n'||c==' '||c=='\r')c=getchar();while(c!='\n'&&c!=' '&&c!='\r')str.push_back(c),c=getchar();return*this;}Reader(){}}cin;const char endl='\n';struct Writer{typedef __int128 mxdouble;template<typename T>typename std::enable_if_t<std::is_class<T>::value,Writer&>operator<<(T x){for(auto &y:x)*this<<y<<between;*this<<'\n';return *this;}template<typename T>typename std::enable_if_t<is_integral_ex<T>::value,Writer&>operator<<(T x){if(x==0)return putchar('0'),*this;if(x<0)putchar('-'),x=-x;static int sta[45];int top=0;while(x)sta[++top]=x%10,x/=10;while(top)putchar(sta[top]+'0'),--top;return*this;}template<typename T>typename std::enable_if_t<is_floating_point_ex<T>::value,Writer&>operator<<(T x){if(x<0)putchar('-'),x=-x;x+=pow(10,-Setprecision)/2;mxdouble _=x;x-=(T)_;static int sta[45];int top=0;while(_)sta[++top]=_%10,_/=10;if(!top)putchar('0');while(top)putchar(sta[top]+'0'),--top;putchar('.');for(int i=0;i<Setprecision;i++)x*=10;_=x;while(_)sta[++top]=_%10,_/=10;for(int i=0;i<Setprecision-top;i++)putchar('0');while(top)putchar(sta[top]+'0'),--top;return*this;}template<typename T>typename std::enable_if_t<is_char<T>::value,Writer&>operator<<(T c){putchar(c);return*this;}Writer&operator<<(char*str){int cur=0;while(str[cur])putchar(str[cur++]);return *this;}Writer&operator<<(const char*str){int cur=0;while(str[cur])putchar(str[cur++]);return*this;}Writer&operator<<(std::string str){int st=0,ed=str.size();while(st<ed)putchar(str[st++]);return*this;}Writer(){}}cout;}
#define cin Fastio::cin
#define cout Fastio::cout
#define endl Fastio::endl

void solve();
main()
{
	int t=1;
	// cin>>t;
	while(t--)solve();
}
int flow[800005],dis[200005],arc[200005];
int n,m,s,t;
vector<pair<int,int>>e[200005];
bool bfs(int s,int t)
{
	for(int x=1;x<=n;x++)
	dis[x]=1e9;
	dis[s]=0;
	queue<int>q;
	q.push(s);
	while(!q.empty())
	{
		int u=q.front();
		if(u==t)return 1;
		q.pop();
		for(auto [v,id]:e[u])
		if(flow[id]&&dis[v]>dis[u]+1)
		{
			dis[v]=dis[u]+1;
			q.push(v);
		}
	}
	return 0;
}
long long dfs(int u,int t,long long lim)
{
	if(u==t)return lim;
	long long fl=0;
	for(int &x=arc[u];x<e[u].size();x++)
	{
		auto [v,id]=e[u][x];
		if(dis[v]!=dis[u]+1||!flow[id])continue;
		long long nf=dfs(v,t,min<long long>(lim,flow[id]));
		flow[id]-=nf,flow[id^1]+=nf;
		fl+=nf,lim-=nf;
		if(lim==0)break;
	}
	return fl;
}
long long dinic(int s,int t)
{
	long long res=0;
	while(bfs(s,t))
	{
		for(int x=1;x<=n;x++)
		arc[x]=0;
		res+=dfs(s,t,1e18);
	}
	return res;
}
void solve()
{
	int n1,n2;
	cin>>n1>>n2>>m;
	n=n1+n2+2;
	s=n-1,t=n;
	int ct=0;
	vector<tuple<int,int,int>>tp;
	for(int x=0;x<m;x++)
	{
		int u,v;
		cin>>u>>v;
		u++,v++;
		v+=n1;
		tp.emplace_back(ct,u,v);
		flow[2*ct]=1;
		flow[2*ct+1]=0;
		e[u].emplace_back(v,2*ct);
		e[v].emplace_back(u,2*ct+1);
		++ct;
	}
	for(int x=1;x<=n1;x++)
	{
		int u=s,v=x;
		flow[2*ct]=1;
		flow[2*ct+1]=0;
		e[u].emplace_back(v,2*ct);
		e[v].emplace_back(u,2*ct+1);
		++ct;
	}
	for(int x=1;x<=n2;x++)
	{
		int u=x+n1,v=t;
		flow[2*ct]=1;
		flow[2*ct+1]=0;
		e[u].emplace_back(v,2*ct);
		e[v].emplace_back(u,2*ct+1);
		++ct;
	}
	cout<<dinic(s,t)<<endl;
	for(auto [id,u,v]:tp)
	if(flow[id^1])cout<<u-1<<' '<<v-n1-1<<endl;
}