#include <iostream>
#include <cstdio>
#include <vector>

#define NMAX 10005

using namespace std;

int N,M,E;
vector<int> graf[NMAX];


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

int st[NMAX],dr[NMAX];
int viz[NMAX];
int nr;
void reset()
{
    for(int i=1;i<=N;i++)
        viz[i]=0;
}

bool cupleaza(int nod)
{
    if(viz[nod]==1)
        return 0;
    viz[nod]=1;
    for(vector<int>::iterator ii=graf[nod].begin();ii!=graf[nod].end();ii++)
    {
        int x= *ii;
        if(dr[*ii] == 0 || cupleaza(dr[*ii]) == 1)
        {

            dr[*ii]=nod;
            st[nod]=*ii;
            viz[nod]=1;
            return 1;
        }

    }
    return 0;
}

void rezolva()
{
    int ok=1;
    while(ok)
    {
    ok=0;
    reset();
    for(int i=1;i<=N;i++)
       if(st[i]==0&&cupleaza(i))
        {
            ok=1;
            nr++;
        }
    }
}

void afisare()
{
    printf("%d\n",nr);
    for(int i=1;i<=N;i++)
        if(st[i])
            printf("%d %d\n",i,st[i]);
}


int main()
{
    freopen("cuplaj.in","r",stdin);
    freopen("cuplaj.out","w",stdout);
    citire();
    rezolva();
    afisare();
    return 0;
}