bpm

#include <bits/stdc++.h>
using namespace std;
#define unmatched -1
#define MAX 505
#define p push_back

int n,m,num;
vector < int > v[MAX];
int match[MAX];
bool vis[MAX];
bool dfs(int x)
{
    vis[x]=1;
    for(int i=0;i<v[x].size();++i){
        int node = v[x][i];
        if(vis[node])continue;
        vis[node]=1;
        if(match[node]==unmatched || dfs(match[node])){
            match[x]=node;
            match[node]=x;
            return 1;
        }
    }
    return 0;
}
int main()
{
    while(cin>>n>>m>>num){
        fill ( match , match+MAX , unmatched);

        for(int i=0;i<num;++i){
            int fr,to;
            scanf("%d %d",&fr,&to);
            v[fr].p(to+n);
            v[to+n].p(fr);
        }

        int sizematching=0;

        for(int i=0;i<n;++i){
            if(match[i]==unmatched){
                fill(vis , vis+MAX , 0);
                if(dfs(i)){
                    sizematching++;
                }
            }
        }
        cout<<sizematching<<endl;
        for(int i=0;i<n;++i){
            if(match[i]!=unmatched){
                cout<<i<<" "<<match[i]-n<<endl;
            }
        }
    }
}