#include <bits/stdc++.h>

using namespace std;

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

int n, m, e, cnt;
int viz[10005], st[10005], dr[10005];
vector <int> V[10005];

void Citire()
{
    int x, y, i;
    fin >> n >> m >> e;
    for(i = 1;i <= e;i++)
    {
        fin >> x >> y;
        V[x].push_back(y);
    }
}

int Cuplare(int nod)
{
    if(viz[nod])
        return 0;
    viz[nod] = 1;
    for(auto x : V[nod])
        if(dr[x] == 0)
        {
            st[nod] = x;
            dr[x] = nod;
            return 1;
        }
    for(auto x : V[nod])
        if(Cuplare(dr[x]))
        {
            st[nod] = x;
            dr[x] = nod;
            return 1;
        }
    return 0;
}

void Solve()
{
    int i, j, ok;
    ok = 1;
    while(ok)
    {
        ok = 0;
        for(i = 1;i <= n;i++)
            viz[i] = 0;
        for(i = 1;i <= n;i++)
            if(st[i] == 0 && Cuplare(i))
            {
                cnt++;
                ok = 1;
            }
    }
    fout << cnt << "\n";
    for(i = 1;i <= n;i++)
        if(st[i])
            fout << i << " " << st[i] << "\n";
}

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