#include<stdio.h>
#include<vector>
#include<string.h>
using namespace std;

#define NMAX 10002

int n,m,e,sol;
int f1[NMAX],f2[NMAX],viz[NMAX];
vector<int> v1[NMAX],v2[NMAX];

bool cupl(int nod)
{
    if(viz[nod])
        return false;
    viz[nod]=1;

    int x;

    for(int i=0;i<v1[nod].size();++i)
    {
        x=v1[nod][i];
        if(!f2[x])
        {
            f1[nod]=x;
            f2[x]=nod;

            ++sol;
            return true;
        }
    }

    for(int i=0;i<v1[nod].size();++i)
    {
        x=v1[nod][i];
        if(cupl(f2[x]))
        {
            f1[nod]=x;
            f2[x]=nod;

            return true;
        }
    }
    return false;
}

int main()
{
    freopen("cuplaj.in","r",stdin);
    freopen("cuplaj.out","w",stdout);
    int x,y;
    bool ok=true;

    scanf("%d%d%d",&n,&m,&e);
    for(int i=1;i<=e;++i)
    {
        scanf("%d%d",&x,&y);
        v1[x].push_back(y);
        v2[y].push_back(x);
    }

    while(ok)
    {
        ok=false;
        memset(viz,0,sizeof(viz));

        for(int i=1;i<=n;++i)
            if(!f1[i])
                ok|=cupl(i);
    }

    printf("%d\n",sol);
    for(int i=1;i<=n;++i)
        if(f1[i])
            printf("%d %d\n",i,f1[i]);

    return 0;
}