#include<iostream>
#include<set>
#include<vector>
#include<algorithm>
#include<cmath>
#include<map>
#include<string>
#include<queue>
#include<fstream>
#include<iomanip>
using namespace std;
int u, mt[100], used[100];
vector<int> g[100];
vector<pair<int, int> > pr;
bool khun(int v)
{
    if (used[v] == u)
        return false;
    used[v] = u;
    for (int i = 0; i < g[v].size(); i++)
    {
        int to = g[v][i];
        if (mt[to] == -1 || khun(mt[to]))
        {
            mt[to] = v;
            return true;
        }
    }
    return false;
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n, k, m, x, y;
    memset(mt, -1, 100);
    cin >> n >> k >> m;
    for (int i = 0; i < m; i++)
    {
        cin >> x >> y;
        x--;
        y--;
        g[x].push_back(y);
    }
    for (int i = 0; i < n; i++)
    {
        u = i + 1;
        khun(i);
    }
    for (int i = 0; i < k; i++)
        if (mt[i] != -1)
            pr.push_back(make_pair(mt[i] + 1, i + 1));
    cout << pr.size() << endl;
    for (int i = 0; i < pr.size(); i++)
        cout << pr[i].first << ' ' << pr[i].second << endl;
    return 0;
}