#include <cstdio>
#include <vector>
using namespace std;

vector<int> v[10010];
int n,m,e,ok = 1,x,y,viz[10010],S[10010],D[10010],C,i,creste(int);

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

    scanf("%d%d%d",&n,&m,&e);
    for(;e;e--)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
    }

    while(ok)
    {
        ok = 0;
        for(i=1;i<=n;i++)
            viz[i] = 0;
        for(i=1;i<=n;i++)
            if(!D[i]&&creste(i))
            {
                C++;
                ok = 1;
            }
    }
    printf("%d\n",C);
    for(i=1;i<=n;i++)
        if(D[i])
            printf("%d %d\n",i,D[i]);

    return 0;
}
int creste(int nod)
{
    if(viz[nod])
        return 0;
    viz[nod] = 1;
    for(auto vec:v[nod])
        if(!S[vec])
        {
            D[nod] = vec;
            S[vec] = nod;
            return 1;
        }
    for(auto vec:v[nod])
        if(creste(S[vec]))
        {
            D[nod] = vec;
            S[vec] = nod;
            return 1;
        }
    return 0;
}