#include <bits/stdc++.h>
using namespace std;
int n, m, k, r = 0, c = 0, q = true, b = false;
void move() {
  if ((r == n - 1 or r == 0) and q == false) {
    c++;
    q = true;
    b = (r == n - 1 ? true : false);
    return;
  }
  if (b == false)
    r++;
  else
    r--;
  q = false;
}
int main() {
  cin >> n >> m >> k;
  for (int i = 1; i < k; i++) {
    cout << 2 << " ";
    cout << r + 1 << " " << c + 1 << " ";
    move();
    cout << r + 1 << " " << c + 1 << endl;
    move();
  }
  cout << (n * m) - 2 * (k - 1) << " ";
  for (int i = 0; i < (n * m) - 2 * (k - 1); i++) {
    cout << r + 1 << " " << c + 1 << " ";
    move();
  }
  cout << endl;
}
