#include <iostream>
#include <stdio.h>
#include <vector>
#include <cstring>
#define NMax 10005
using namespace std;
vector<int> Graf[NMax];
int N,M,E,x,y,CuplajMaxim;
int M1[NMax],M2[NMax];
bool mark[NMax],cuplaj;

void Read()
{
    scanf("%d%d%d",&N,&M,&E);
    for(int i=1;i<=E;i++)
    {
        scanf("%d%d",&x,&y);
        Graf[x].push_back(y);
    }
}

bool Cuplaj(int x)
{
    if(mark[x])
        return false;
    mark[x]=true;
    for(vector<int>::iterator it=Graf[x].begin();it!=Graf[x].end();it++)
        if(M2[*it]==0)
        {
            M1[x]=*it;
            M2[*it]=x;
            return true;
        }
    for(vector<int>::iterator it=Graf[x].begin();it!=Graf[x].end();it++)
        if(Cuplaj(M2[*it]))
        {
            M1[x]=*it;
            M2[*it]=x;
            return true;
        }
    return false;
}

void Solve()
{
    cuplaj=true;
    while(cuplaj==true)
    {
        cuplaj=false;
        memset(mark,false,sizeof(mark));
        for(int i=1;i<=N;i++)
            if(M1[i]==0 && Cuplaj(i)==true)
            {
                cuplaj=true;
                CuplajMaxim++;
            }
    }
}

inline void Write()
{
    printf("%d\n",CuplajMaxim);
    for(int i=1;i<=N;i++)
        if(M1[i])
        printf("%d %d\n",i,M1[i]);
}

int main()
{
    freopen("cuplaj.in","r",stdin);
    freopen("cuplaj.out","w",stdout);
    Read();
    Solve();
    Write();
}