#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cout << fixed;
  cout.precision(10);
  int n, m, k;
  cin >> n >> m >> k;
  int cnt = 0, res = 1, ct = 0;
  k--;
  if (k) {
    cout << "2 ";
  } else {
    cout << n * m << " ";
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (res) {
        cout << i << " " << j << " ";
      } else {
        cout << i << " " << m - j + 1 << " ";
      }
      cnt++;
      ct++;
      if (ct % 2 == 0 and k) {
        k--;
        cout << "\n";
        if (k)
          cout << "2 ";
        else
          cout << n * m - ct << " ";
      }
    }
    res ^= 1;
  }
  return 0;
}
