#include<fstream>
#include<vector>
#include<queue>
using namespace std;
ifstream fin("cuplaj.in");
ofstream fout("cuplaj.out");
vector <int> v[10001];
queue <int> q;
int viz[10001], c[10001][10001], f[10001][10001], t[10001];
int s, d, n, m, a, b, flow, i, j, sr, des;

int bfs(int st){
    int i, j;
    while (!q.empty())
        q.pop();
    for (i = 1; i <= n; i++)
        viz[i] = 0;
    viz[st] = 1; q.push(st);
    while (!q.empty()){
        int nod = q.front(); q.pop();
        for (i = 0; i < v[nod].size(); i++){
            int fiu = v[nod][i];
            if (viz[fiu] == 0 and c[nod][fiu] != f[nod][fiu]){
                viz[fiu] = 1;
                t[fiu] = nod;
                q.push(fiu);
                if (fiu == des)
                    return 1;
            }
        }
    }
    return 0;
}

int main(){
    fin >> s >> d >> m;
    n = s + d + 2;
    sr = s + d + 1; des = s + d + 2;
    for (i = 1; i <= m; i++){
        fin >> a >> b;
        v[a].push_back(b + s);
        v[b + s].push_back(a);
        c[a][b + s] = 1;
        v[sr].push_back(a);
        v[a].push_back(sr);
        c[sr][a] = 1;
        v[b + s].push_back(des);
        v[des].push_back(b + s);
        c[b + s][des] = 1;
    }
    while (bfs(sr)){
        int nod = des; int fmini = 1;
        while (nod != sr){
            fmini = min(fmini, c[t[nod]][nod] - f[t[nod]][nod]);
            nod = t[nod];
        }
        nod = des;
        while (nod != sr){
            f[t[nod]][nod] += fmini;
            f[nod][t[nod]] -= fmini;
            nod = t[nod];
        }
        flow += fmini;
    }
    fout << flow << '\n';
    for (i = 1; i <= n; i++)
        for (j = 1; j <= n; j++)
            if (f[i][j] == 1 and i != sr and j != des)
                fout << i << " " << j - s << '\n';

}