#include <bits/stdc++.h>
using namespace std;
int n, m, k;
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> m >> k;
  int sl = n * m;
  int div = sl / k;
  int mod = sl % k;
  int tmp = 0;
  k--;
  for (int i = 1; i <= n; i++)
    for (int j = i & 1 ? 1 : m; (j <= m && i & 1) || (j >= 1 && !(i & 1));
         j += (i & 1 ? 1 : -1)) {
      if (!tmp) cout << (k ? div : div + mod) << " ";
      cout << i << " " << j << " ";
      tmp++;
      if (tmp == (k ? div : div + mod)) {
        k--;
        tmp = 0;
        cout << endl;
      }
    }
  return 0;
}
