#include <bits/stdc++.h>
#define nmax 10005

using namespace std;

ifstream fin("cuplaj.in");
ofstream fout("cuplaj.out");

int N, M, E, st[nmax], dr[nmax], ans;
bool viz[nmax];
vector <int> L[nmax];

inline bool Cupleaza(int k)
{
    if(viz[k]) return false;
    viz[k] = true;
    for(auto i : L[k])
    {
        if(!dr[i])
        {
            st[k] = i;
            dr[i] = k;
            return true;
        }
    }
    for(auto i : L[k])
        if(Cupleaza(dr[i]))
        {
            st[k] = i;
            dr[i] = k;
            return true;
        }
    return false;
}

inline void Citire()
{
    int x, y, i;
    fin >> N >> M >> E;
    for (i = 1; i <= E; ++i)
    {
        fin >> x >> y;
        L[x].push_back(y);
    }
}

inline void Rezolva()
{
    int i, gata = 0;
    while(!gata)
    {
        gata = 1;
        for(i = 1; i <= N; i++) viz[i] = 0;
        for(i = 1; i <= N; i++)
            if(st[i] == 0 && Cupleaza(i))
            {
                ++ans;
                gata = 0;
            }
    }
    fout << ans << "\n";
    for(i = 1; i <= N; i++)
        if(st[i])
          fout << i << " " << st[i] << "\n";
    fout.close();
}

int main()
{
    Citire();
    Rezolva();
    return 0;
}