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

const int NMAX = 2005;
int capacitate[NMAX + 1][NMAX + 1], flux[NMAX + 1][NMAX + 1];
int vis[NMAX + 1], p[NMAX + 1];
vector<int> G[NMAX + 1];
int n, m, e;

int bfs(int s, int d) {
    for(int i = 0; i <= n+m+1; i++) {
        vis[i] = 0;
        p[i] = -1;
    }
    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;
                q.push(vecin);
                p[vecin] = nod;
            }
        }
    }
    if(vis[d] == 0) {
        return 0;
    }
    vector<int> path;
    while(d != -1) {
        path.push_back(d);
        d = p[d];
    }
    reverse(path.begin(), path.end());
    int flow = 1e9;
    for(int i = 0; i < path.size() - 1; i++) {
        int x = path[i];
        int y = path[i + 1];
        flow = min(flow, capacitate[x][y] - flux[x][y]);
    }
    for(int i = 0; i < path.size() - 1; i++) {
        int x = path[i];
        int y = path[i + 1];
        flux[x][y] += flow;
        flux[y][x] -= flow;
    }
    return flow;
}

int main() {
    ifstream fin("cuplaj.in");
    ofstream fout("cuplaj.out");
    fin >> n >> m >> e;
    if (n+m+2 >= NMAX) {
        fout << 0 << '\n';
        return 0;
    }
    for(int i = 1; i <= e; i++) {
        int x, y, c;
        fin >> x >> y;
        capacitate[x][n+y] = 1;
        G[x].push_back(n+y);
        G[n+y].push_back(x);
    }
    for (int i = 1; i <= n; i++) {
        capacitate[0][i] = 1;
        G[0].push_back(i);
        G[i].push_back(0);
    }

    for (int i = n + 1; i <= n + m + 1; i++) {
        capacitate[i][n+m+1] = 1;
        G[i].push_back(n+m+1);
        G[n+m+1].push_back(i);
    }
    int maxflow = 0;
    while(true) {
        int flow = bfs(0, n+m+1);
        if(flow == 0) {
            break;
        }
        maxflow += flow;
    }
    fout << maxflow;
    for (int i = 1; i <= n; i++) {
        for (int j = n + 1; j <= n+m; j++) {
            if (flux[i][j] == 1)
                fout << i << " " << j - n << endl;
        }
    }
    return 0;
}