#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 1e5 + 5;
const int M = 1e6;
const long long INF = (long long)(1e18);
const int inf = 1e9;
const long long MOD = 100000000LL;
void solve() {}
int n, m, k;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m >> k;
  int row = 1;
  int col = 1;
  int nxt = 1;
  int memo = k;
  while (k > 1) {
    cout << "2 " << row << " " << col << " ";
    col += nxt;
    if (col > m || col < 1) {
      row++;
      col -= nxt;
      nxt *= -1;
    }
    cout << row << " " << col << "\n";
    col += nxt;
    if (col > m || col < 1) {
      row++;
      col -= nxt;
      nxt *= -1;
    }
    k--;
  }
  cout << n * m - 2 * (memo - 1) << " ";
  while (row <= n) {
    cout << row << " " << col << " ";
    col += nxt;
    if (col > m || col < 1) {
      row++;
      col -= nxt;
      nxt *= -1;
    }
  }
  return 0;
}
