#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  vector<pair<int, int>> p;
  for (int i = 1; i <= n; i++) {
    if (i & 1) {
      for (int j = 1; j <= m; j++) {
        p.push_back({i, j});
      }
    } else {
      for (int j = m; j > 0; j--) p.push_back({i, j});
    }
  }
  int len = p.size();
  int now = 0;
  for (int i = 1; i < k; i++) {
    cout << "2 ";
    for (int j = 0; j < 2; j++) {
      cout << p[now].first << " " << p[now].second << " ";
      now++;
    }
    cout << endl;
  }
  cout << len - now << " ";
  for (int i = now; i < len; i++)
    cout << p[i].first << " " << p[i].second << " ";
  cout << endl;
  return 0;
}
