#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  int sz = 2;
  int i = 0, j = 0, cnt = 1;
  int pnt = 0;
  if (k != 1) cout << sz;
  for (i = 0; i < n && cnt < k; i++) {
    if (i % 2) {
      j = m - 1;
      for (; j >= 0; j--) {
        cout << " " << i + 1 << " " << j + 1;
        pnt++;
        if (pnt == sz) {
          cout << endl;
          pnt = 0;
          cnt++;
          if (cnt == k) {
            j--;
            break;
          }
          cout << sz;
        }
      }
    } else {
      j = 0;
      for (; j < m; j++) {
        cout << " " << i + 1 << " " << j + 1;
        pnt++;
        if (pnt == sz) {
          cout << endl;
          pnt = 0;
          cnt++;
          if (cnt == k) {
            j++;
            break;
          }
          cout << sz;
        }
      }
    }
    if (cnt == k) break;
  }
  cnt = n * m - (k - 1) * sz;
  cout << cnt;
  for (; i < n && cnt; i++) {
    if (i % 2) {
      for (; j >= 0; j--) {
        cout << " " << i + 1 << " " << j + 1;
        cnt--;
        if (!cnt) break;
      }
      j = 0;
    } else {
      for (; j < m; j++) {
        cout << " " << i + 1 << " " << j + 1;
        cnt--;
        if (!cnt) break;
      }
      j = m - 1;
    }
  }
  cout << endl;
  return 0;
}
