#include <iostream>
#include <cstdio>
#include <fstream>
#include <vector>
#include <bitset>
#include <cassert>
#include <cstring>
#include <algorithm>
#define NMAX 10009
using namespace std;

int n, m, e, dr[NMAX], st[NMAX], sol;
vector<int> G[NMAX];
bitset<NMAX> viz;

void read_input() {
    cin >> n >> m >> e;

    for (int i = 1; i <= e; ++i) {
          int x, y;
          cin >>  x >> y;

          G[x].push_back(y);
    }
}


int cupleaza(int node) {
     if (viz[node]) {
          return 0;
     }

     viz[node] = 1;

     for (auto it : G[node]) {
          if (!st[it]) {
               dr[node] = it;
               st[it] = node;
               return 1;
          }
     }

     for (auto it : G[node]) {
          if (st[it] && cupleaza(st[it])) {
               dr[node] = it;
               st[it] = node;
               return 1;
          }
     }

     return 0;
}
void Cuplaj() {
     sol = 0;

     bool ready = false;
     while (!ready) {
          ready = true;
          for (int i = 1; i <= n; ++i) {
               viz[i] = 0;
          }

          for (int i = 1; i <= n; ++i) {
               if (!dr[i] && cupleaza(i)) {
                    sol++;
                    ready = false;
               }
          }
     }

     cout << sol << "\n";
     for (int i = 1; i <= n; ++i) {
          if (dr[i]) {
               cout << i << " " << dr[i] << "\n";
          }
     }
}

int main() {
    assert( freopen("cuplaj.in", "r", stdin) != NULL);
    assert( freopen("cuplaj.out", "w", stdout) != NULL) ;

    read_input();
    Cuplaj();

    return 0;
}