#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define pf push_front
#define MOD 1000000007
#define MAX 10005

using namespace std;

vector < int > v[MAX];
int p[MAX];
bool viz[MAX];

bool dfs(int nod);

int main()
{
    ifstream cin("cuplaj.in");
    ofstream cout("cuplaj.out");
    int l, r, m, x, y, i, nr = 0;

    cin >> l >> r >> m;
    for(i = 1; i <= m; i++)
    {
        cin >> x >> y;
        v[x].pb(y);
    }

    for(i = 1; i <= r; i++) p[i] = -1;
    for(x = 1; x <= l; x++)
    {
        for(i = 1; i <= l; i++) viz[i] = 0;
        if(dfs(x) == 1) nr++;
    }

    cout << nr << '\n';
    for(i = 1; i <= r; i++) if(p[i] != -1) cout << p[i] << ' ' << i << '\n';

    return 0;
}

bool dfs(int nod)
{
    viz[nod] = 1;
    for (int x: v[nod]) if(p[x] == -1 || (viz[p[x]] == 0 && dfs(p[x]) == 1))
        {
            p[x] = nod;
            return 1;
        }
    return 0;
}