#include <bits/stdc++.h>
using namespace std;

const int NMAX = 2505;
int capacitate[NMAX + 1][NMAX + 1];
int flux[NMAX + 1][NMAX + 1];
int vis[NMAX + 1], p[NMAX + 1];
vector<int> G[NMAX + 1];
int n, m;

int bfs(int s, int d) {
    for(int i = 1; i <= n; i++) {
        vis[i] = 0;
        p[i] = 0;
    }
    queue<int> q;
    q.push(s);
    vis[s] = 1;
    while(!q.empty()) {
        int nod = q.front();
        q.pop();
        for(auto vecin : G[nod]) {
            if(!vis[vecin] && capacitate[nod][vecin] - flux[nod][vecin] > 0) {
                vis[vecin] = 1;
                p[vecin] = nod;
                q.push(vecin);
            }
        }
    }
    if(!vis[d]) {
        return 0;
    }
    vector<int> path;
    int x = d;
    while(x != 0) {
        path.push_back(x);
        x = p[x];
    }
    reverse(path.begin(), path.end());
    int flow = 1e9;
    for(int i = 0; i < path.size() - 1; i++) {
        int a = path[i];
        int b = path[i + 1];
        flow = min(flow, capacitate[a][b] - flux[a][b]);
    }
    for(int i = 0; i < path.size() - 1; i++) {
        int a = path[i];
        int b = path[i + 1];
        flux[a][b] += flow;
        flux[b][a] -= flow;
    }
    return flow;
}

int main() {
    ifstream cin("cuplaj.in");
    ofstream cout("cuplaj.out");

    int n_st, m_dr, e_muchii;
    cin >> n_st >> m_dr >> e_muchii;

    n = n_st + m_dr + 2;
    int s = 1;
    int d = n;

    for(int i = 1; i <= n_st; i++) {
        capacitate[s][i + 1] = 1;
        G[s].push_back(i + 1);
        G[i + 1].push_back(s);
    }

    for(int i = 1; i <= m_dr; i++) {
        int nod = n_st + 1 + i;
        capacitate[nod][d] = 1;
        G[nod].push_back(d);
        G[d].push_back(nod);
    }

    for(int i = 1; i <= e_muchii; i++) {
        int u, v;
        cin >> u >> v;
        int nod_st = u + 1;
        int nod_dr = n_st + 1 + v;

        capacitate[nod_st][nod_dr] = 1;
        G[nod_st].push_back(nod_dr);
        G[nod_dr].push_back(nod_st);
    }

    int maxflow = 0;
    while(true) {
        int flow = bfs(s, d);
        if(flow == 0) {
            break;
        }
        maxflow += flow;
    }

    cout << maxflow << "\n";

    for(int i = 1; i <= n_st; i++) {
        for(int j = 1; j <= m_dr; j++) {
            if(flux[i + 1][n_st + 1 + j] == 1) {
                cout << i << " " << j << "\n";
            }
        }
    }
    return 0;
}