#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  int sum = 0;
  int x = (n * m) / k;
  int y = (n * m) % k;
  bool flag = false;
  int r = 0;
  for (int i = 0; i < n; i++) {
    if (i % 2 == 0) {
      for (int j = 0; j < m; j++) {
        if (sum % x == 0 && flag == false) {
          if (r == k - 1) {
            flag = true;
            cout << endl << x + y << " ";
          } else
            cout << endl << x << " ";
          r++;
        }
        cout << i + 1 << " " << j + 1 << " ";
        sum++;
      }
    } else {
      for (int j = m - 1; j >= 0; j--) {
        if (sum % x == 0 && flag == false) {
          if (r == k - 1) {
            cout << endl << x + y << " ";
            flag = true;
          } else
            cout << endl << x << " ";
          r++;
        }
        cout << i + 1 << " " << j + 1 << " ";
        sum++;
      }
    }
  }
}
