#include <bits/stdc++.h>
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast,no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("fast-math")
using namespace std;

const int MAXN = 202;
int a, b, n, m;
bool adj[MAXN][MAXN];
int kek[MAXN];
bool used[MAXN];
int cnt = 0;

bool kuhn(int v) {
    used[v] = true;
    for (int i = a + 1; i <= n; i++) {
        if (!adj[i][v]) continue;
        if (!used[i]) {
            if (kek[i] == 0 || kuhn(kek[i])) {
                kek[i] = v;
                return true;
            }
        }
    }
    return false;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> a >> b >> m;
    n = a + b;
    for (int i = 0; i < m; i++) {
        int u, v;
        cin >> u >> v;
        v += a;
        adj[v][u] = true;
    }
    for (int i = 1; i <= a; i++) {
        memset(used, false, n);
        if (kek[i] == 0) {
            if (kuhn(i)) {
                cnt++;
            }
        }
    }
    cout << cnt << '\n';
    for (int i = a + 1; i <= n; i++) {
        if (kek[i] != 0) {
            cout << kek[i] << ' ' << i - a << '\n';
        }
    }
    fflush(stdout);
    return 0;
}