#include<bits/stdc++.h>
using namespace std;
#define ll long long
namespace IO{//by cyffff
	int len=0;
	char ibuf[(1<<21)+1],*iS,*iT,out[(1<<25)+1];
	#if ONLINE_JUDGE
	#define gh() (iS==iT?iT=(iS=ibuf)+fread(ibuf,1,(1<<21)+1,stdin),(iS==iT?EOF:*iS++):*iS++)
 	#else
	#define gh() getchar()
	#endif
	#define reg register
	inline int read(){
		reg char ch=gh();
		reg int x=0;
		reg char t=0;
		while(ch<'0'||ch>'9')   t|=ch=='-',ch=gh();
		while(ch>='0'&&ch<='9') x=x*10+(ch^48),ch=gh();
		return t?-x:x;
	}
	inline void putc(char ch){
		out[len++]=ch;
	}
	template<class T>
	inline void write(T x){
		if(x<0)putc('-'),x=-x;
		if(x>9)write(x/10);
		out[len++]=x%10+48;
	}
	inline void flush(){
		fwrite(out,1,len,stdout);
		len=0;
	}
	inline char getc(){
		char ch=gh();
		while(ch<'A'||ch>'Z') ch=gh();
		return ch;
	}
}
using IO::read;
using IO::write;
using IO::flush;
using IO::getc;
using IO::putc;
const int N=100+10,M=1e4+10;
const ll INF=1e10;
int n1,n2,m,head[N],cnt=1;
struct Edge{
	int to,nxt,fl;
}a[M];
inline void Add(int u,int v,int w){
	a[++cnt]={v,head[u],w},head[u]=cnt;
}
inline void add(int u,int v,int w){
	Add(u,v,w),Add(v,u,0);
}
int thd[N],dep[N],s,t;
inline bool bfs(){
	for(int i=1;i<=t;i++)
		thd[i]=head[i],dep[i]=t+1;
	queue<int>q;
	q.push(s),dep[s]=0;
	while(!q.empty()){
		int x=q.front();
		q.pop();
		for(int i=head[x];i;i=a[i].nxt){
			int t=a[i].to;
			if(a[i].fl&&dep[t]>dep[x]+1)
				dep[t]=dep[x]+1,q.push(t);
		}
	}
	return dep[t]<=t;
}
inline ll dfs(int x,ll fl){
	if(x==t) return fl;
	ll s=0;
	for(int i=thd[x];i&&fl;i=a[i].nxt){
		thd[x]=i;
		int t=a[i].to;
		if(dep[t]==dep[x]+1&&a[i].fl){
			ll res=dfs(t,min(fl,a[i].fl+0ll));
			a[i].fl-=res,a[i^1].fl+=res,fl-=res,s+=res;
		}
	}
	return s;
}
inline ll dinic(){
	ll sum=0;
	while(bfs())
		sum+=dfs(s,INF);
	return sum;
}
int main(){
	n1=read(),n2=read(),m=read(),s=n1+n2+1,t=s+1;
	for(int i=1;i<=n1;i++)
		add(s,i,1);
	for(int i=n1+1;i<=n1+n2;i++)
		add(i,t,1);
	for(int i=1;i<=m;i++){
		int u=read()+1,v=read()+1+n1;
		add(u,v,1);
	}
	write(dinic()),putc('\n');
	for(int i=1;i<=n1;i++){
		for(int j=head[i];j;j=a[j].nxt){
			int t=a[j].to;
			if(t<=n1+n2&&!a[j].fl) write(i-1),putc(' '),write(t-n1-1),putc('\n');
		}
	}
	flush();
}