#include <bits/stdc++.h>

using namespace std;

const int NMAX = 1e4;
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 = 0; i <= n; i ++) {
        vis[i] = 0;
    }
    queue <int> q;
    q.push(s);
    vis[s] = 1;
    while(!q.empty()) {
        int nod = q.front();
        q.pop();
        for(auto& v : G[nod]) {
            if(!vis[v] && capacitate[nod][v] - flux[nod][v] > 0) {
                vis[v] = 1;
                p[v] = nod;
                q.push(v);
            }
        }
    }

    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 l, r, e;
    cin >> l >> r >> e;
    n = l + r + 2;
    for(int i = 1; i <= e; i ++) {
        int x, y;
        cin >> x >> y;
        y += l;
        G[x].push_back(y);
        G[y].push_back(x);
        capacitate[x][y] = 1;
    }

    int flux_maxim = 0;
    int s = 0;
    int d = l + r + 1;

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

    for(int i = l + 1; i < d; i ++) {
        G[d].push_back(i);
        G[i].push_back(d);
        capacitate[i][d] = 1;
    }
    
    int flow;
    while((flow = bfs(s, d)) > 0) {
        flux_maxim += flow;
    }
    
    cout << flux_maxim << "\n";

    for(int i = 1; i <= l; i ++) {
        for(int j = l + 1; j <= l + r; j ++) {
            if(flux[i][j] == 1) {
                cout << i << ' ' << j - l << '\n';
            }
        }
    }

    return 0;
}