#pragma GCC optimize("O3")
#include<bits/stdc++.h>
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define in insert
#define er erase
#define fd find
#define fr first
#define sc second
typedef long long ll;
typedef long double ld;
const ll INF=0x3f3f3f3f3f3f3f3f;
const ll llinf=(1LL<<62);
const int inf=(1<<30);
const int nmax=1e4+50;
const int mod=1e9+7;
using namespace std;
int n,m,i,vl[nmax],v[nmax],e,ans,x,y,j;
vector<int>g[nmax];
int dfs(int x)
{
	for(int i=0;i<g[x].size();i++)
	{
		int y=g[x][i];
		if(v[y])continue;
		v[y]=1;
		if(vl[y]==-1 || dfs(vl[y]))
		{	
			vl[y]=x;
			return 1;
		}
	}
	return 0;
}
int main()
{
	freopen("cuplaj.in","r",stdin);
	freopen("cuplaj.out","w",stdout);
	//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
	ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
	cin>>n>>m>>e;
	while(e--)
	{
		cin>>x>>y;
		g[x].pb(y);
	}
	for(i=1;i<=m;i++)vl[i]=-1;
	for(i=1;i<=n;i++)
	{
		for(j=1;j<=m;j++)v[j]=0;
		if(dfs(i))ans++;
	}
	cout<<ans<<'\n';
	for(i=1;i<=m;i++)if(vl[i]!=-1)cout<<vl[i]<<' '<<i<<'\n';
    return 0;
}