#include <bits/stdc++.h>
#define cin fin
#define cout fout
using namespace std;

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

int n, m, e;
vector <int> adj[20004];
int cost[2004][2004];
int father[20004];

bool findBfs() {
    queue <int> q;
    bitset <20004> reached;
    q.push(0);

    while (!q.empty()) {
        int front = q.front();
        q.pop();
        reached[front] = 1;

        if (front == n + m + 1) {
            return true;
        }

        for (int next : adj[front]) {
            if (front < next && cost[front][next] < 1 && !reached[next]) {
                reached[next] = 1;
                father[next] = front;
                q.push(next);
            } else if (front > next && cost[front][next] && !reached[next]) {
                reached[next] = 1;
                father[next] = front;
                q.push(next);
            }
        }
    }

    return false;
}

void update(int currNode) {
    if (currNode == 0) {
        return;
    }

    update(father[currNode]);

    cost[father[currNode]][currNode] += 1;
    cost[currNode][father[currNode]] -= 1;
}

int main() {
    cin >> n >> m >> e;
    for (int i = 0; i < e; ++i) {
        int l, r;
        cin >> l >> r;
        adj[l].push_back(n + r);
        adj[n + r].push_back(l);
    }

    for (int i = 1; i <= n; ++i) {
        adj[0].push_back(i);
    }

    for (int i = 1; i <= m; ++i) {
        adj[n + i].push_back(n + m + 1);
    }

    while (findBfs()) {
        update(n + m + 1);
    }

    vector <pair <int, int> > cuplaj;
    for (int i = 1; i <= n; ++i) {
        for (int next : adj[i]) {
            if (cost[i][next] == 1) {
                cuplaj.push_back({i, next});
            }
        }
    }

    cout << cuplaj.size() << '\n';
    for (auto curr : cuplaj) {
        cout << curr.first << ' ' << curr.second - n<< '\n';
    }




    return 0;
}