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