#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
const double EPS = 1e-9;
const int N = 2e5 + 9;
int n, m, k;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m >> k;
  int t = n * m - (k - 1) * 2;
  int c = 0;
  for (int i = 1; i <= n; i++) {
    if (i % 2) {
      for (int j = 1; j <= m; j++) {
        if (k > 1) {
          if (c == 0)
            cout << "2 " << i << " " << j << " ";
          else
            k--, cout << i << " " << j << endl;
          c++;
          c %= 2;
        } else {
          if (c == 0)
            cout << t << " " << i << " " << j << " ";
          else
            cout << i << " " << j << " ";
          c++;
        }
      }
    } else {
      for (int j = m; j >= 1; j--) {
        if (k > 1) {
          if (c == 0)
            cout << "2 " << i << " " << j << " ";
          else
            k--, cout << i << " " << j << endl;
          c++;
          c %= 2;
        } else {
          if (c == 0)
            cout << t << " " << i << " " << j << " ";
          else
            cout << i << " " << j << " ";
          c++;
        }
      }
    }
  }
  return 0;
}
