#include <bits/stdc++.h>
using namespace std;
void Solve() {
  int n, m, k;
  cin >> n >> m >> k;
  vector<pair<int, int>> c;
  for (int i = 1; i <= n; i++) {
    if (i % 2) {
      for (int j = 1; j <= m; j++) {
        c.push_back(make_pair(i, j));
      }
    } else {
      for (int j = m; j >= 1; j--) {
        c.push_back(make_pair(i, j));
      }
    }
  }
  int j = 0;
  for (int i = 0; i < k - 1; i++) {
    cout << "2 " << c[j].first << " " << c[j].second << " " << c[j + 1].first
         << " " << c[j + 1].second << "\n";
    j += 2;
  }
  cout << c.size() - j << " ";
  while (j < c.size()) {
    cout << c[j].first << " " << c[j].second << " ";
    j++;
  }
  cout << "\n";
}
int main() { Solve(); }
