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

const int NMAX = 2005;

int capacitate[NMAX+1][NMAX+1], flux[NMAX+1][NMAX+1];
int viz[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++) {
        viz[i]=0;
        p[i]=-1;
    }
    queue<int> q;
    q.push(s);
    viz[s]=1;
    while (!q.empty()) {
        int nod = q.front();
        q.pop();
        for (auto vecin : G[nod]) {
            if (!viz[vecin] && capacitate[nod][vecin] - flux[nod][vecin] > 0) {
                viz[vecin] =1;
                q.push(vecin);
                p[vecin] = nod;
            }
        }
    }
    if (viz[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;
    for (int i=0; i<e; i++) {
        int x, y;
        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; 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<<"\n";
    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<<"\n";
            }
        }
    }
    return 0;
}