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

const int nmax = 1007;

int n, m, e;
vector<int> adj[nmax];
int cap[nmax][nmax];
int par[nmax];

void bfs() {

  memset(par, -1, sizeof(par));

  queue<int> q;
  q.push(1);
  par[1] = 0;

  while (!q.empty()) {
    int u = q.front(); q.pop();
    for (int v : adj[u]) {
      if (cap[u][v] > 0 && par[v] == -1) {
        par[v] = u;
        if (v != n + m + 2) q.push(v);
      }
    }
  }

}

void solve() {
  
  cin >> n >> m >> e;
  for (int i = 0; i < e; i++) {
    int u, v;
    cin >> u >> v;
    u = u + 1;
    v = v + n + 1;
    adj[u].push_back(v);
    adj[v].push_back(u);
    cap[u][v] = 1;
  }

  for (int i = 2; i <= n + 1; i++) {
    adj[1].push_back(i);
    adj[i].push_back(1);
    cap[1][i] = 1;
  }

  for (int i = n + 2; i <= n + m + 1; i++) {
    adj[i].push_back(n + m + 2);
    adj[n + m + 2].push_back(i);
    cap[i][n + m + 2] = 1;
  }

  int totalFlow = 0;

  for (;;) {
    
    bfs();
    
    if (par[n + m + 2] == -1) break;

    for (int v : adj[n + m + 2]) {
      
      if (par[v] == -1 || cap[v][n + m + 2] == 0) continue;

      int currentFlow = INT_MAX;

      par[n] = v;

      for (int u = n + m + 2; u != 1; u = par[u]) {
        currentFlow = min(currentFlow, cap[par[u]][u]);
      }

      if (currentFlow == 0) continue;
      
      for (int u = n + m + 2; u != 1; u = par[u]) {
        cap[par[u]][u] -= currentFlow;
        cap[u][par[u]] += currentFlow;
      }

      totalFlow += currentFlow;
    }
  }

  cout << totalFlow << '\n';
  for (int i = 2; i <= n + 1; i++) {
    for (int v : adj[i]) {
      if (cap[v][i] && v != 1) {
        cout << i - 1 << ' ' << v - n - 1 << '\n';
        break;
      }
    }
  }

}

int main() {

  #ifdef LOCAL
  freopen("file.in", "r", stdin);
  #else
  freopen("cuplaj.in", "r", stdin);
  freopen("cuplaj.out", "w", stdout);
  #endif

  ios_base::sync_with_stdio(false), cin.tie(NULL);

  solve();
}