#include <queue>
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
const int NMAX = 10005;
const int INF = 1000000000;
bool viz[NMAX];
int deUnde[NMAX];
int cap[NMAX][NMAX];
vector <int> vec[2 * NMAX];
bool bfs(int nod, int n) {
  queue <int> q;
  q.push(nod);
  viz[nod] = 1;
  while(!q.empty() && viz[n] == 0) {
    int u = q.front();
    q.pop();
    for(int v : vec[u]) {
      if(viz[v] == 0 && cap[u][v] > 0) {
        viz[v] = 1;
        q.push(v);
        deUnde[v] = u;
      }
    }
  }
  return viz[n];
}

int main() {
  int n, m, e;
  freopen("cuplaj.in", "r", stdin);
  freopen("cuplaj.out", "w", stdout);
  scanf("%d%d%d", &n, &m, &e);
  for(int i = 1; i <= e; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    y += n;
    vec[x].push_back(y);
    vec[y].push_back(x);
    cap[x][y] = 1;
  }
  int s = 0, d = 2 * n + 1;
  for(int i = 1; i <= n; i++) {
    vec[0].push_back(i);
    vec[i].push_back(0);
    cap[0][i] = 1;
  }
  for(int i = 1; i <= m; i++) {
    int x = i + n;
    vec[x].push_back(d);
    vec[d].push_back(x);
    cap[x][d] = 1;
  }
  int sol = 0;
  while(bfs(s, d) == 1) {
    int poz = d;
    int minim = INF;
    while(poz != s) {
      minim = min(minim, cap[deUnde[poz]][poz]);
      poz = deUnde[poz];
    }
    poz = d;
    while(poz != s) {
      cap[deUnde[poz]][poz] -= minim;
      cap[poz][deUnde[poz]] += minim;
      poz = deUnde[poz];
    }
    for(int i = s; i <= d; i++) {
      viz[i] = 0;
    }
    sol += minim;
  }
  printf("%d\n", sol);
  for(int i = 1; i <= n; i++) {
    for(int j = n + 1; j <= m + n; j++) {
      if(cap[i][j] == 0 && cap[j][i] > 0) {
        printf("%d %d\n", i, j - n);
      }
    }
  }
  return 0;
}