#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m, k;
  cin >> n >> m >> k;
  int r = m * n - 2 * (k - 1);
  cout << r << " ";
  int i = 0, j = 0;
  for (; i < n; i++) {
    if (i % 2 == 0) {
      for (j = 0; j < m; j++) {
        cout << i + 1 << " " << j + 1 << " ";
        r--;
        if (r == 0) break;
      }
    } else {
      for (j = m; j > 0; j--) {
        cout << i + 1 << " " << j << " ";
        r--;
        if (r == 0) break;
      }
    }
    if (r == 0) break;
  }
  if (i % 2 == 0) {
    if (j != m)
      j++;
    else
      i++;
  } else {
    if (j != 0)
      j--;
    else
      i++;
  }
  cout << endl;
  r = 2;
  for (; i < n; i++) {
    if (i % 2 == 0) {
      for (; j < m; j++) {
        if (r == 2) cout << r << " ";
        cout << i + 1 << " " << j + 1 << " ";
        r--;
        if (r == 0) {
          cout << endl;
          r = 2;
        }
      }
    } else {
      for (; j > 0; j--) {
        if (r == 2) cout << r << " ";
        cout << i + 1 << " " << j << " ";
        r--;
        if (r == 0) {
          cout << endl;
          r = 2;
        }
      }
    }
    if (r == 0) r = 2;
  }
  return 0;
}
