#include <bits/stdc++.h>
using namespace std;
ifstream fin ("cuplaj.in");
ofstream fout ("cuplaj.out");
const int Nmax =  10005;
int n , m , e , st[Nmax] , dr[Nmax];
bitset < Nmax > viz;
vector < int > L[Nmax];
inline bool Solve(int k)
{
    if(viz[k] == 1)
        return false;
    viz[k] = 1;
    for(auto i : L[k])
        if(!dr[i])
    {
        st[k] = i;
        dr[i] = k;
        return true;
    }
    for(auto i : L[k])
        if(dr[i] && Solve(dr[i]))
    {
        st[k] = i;
        dr[i] = k;
        return true;
    }
    return false;
}
int main()
{
    int x , y , sol = 0;
    bool ok = false;
    fin >> n >> m >> e;
    for(int i = 1 ; i <= e ; i++)
    {
        fin >> x >> y;
        L[x] . push_back(y);
    }
    while(!ok)
    {
        ok = true;
        viz . reset();
        for(int i = 1 ; i <= n ; i++)
            if(!st[i] && Solve(i))
            {
                ++sol;
                ok = false;
            }
    }
    fout << sol << "\n";
    for(int i = 1 ; i <= n ; i++)
        if(st[i])
            fout << i << " " << st[i] << "\n";
    fin.close();
    fout.close();
    return 0;
}