#include <bits/stdc++.h>
using namespace std;
void sol() {
  int n, m, k;
  cin >> n >> m >> k;
  vector<pair<int, int>> v;
  for (int i = 1; i <= n; i++) {
    if (i % 2 == 1) {
      for (int j = 1; j <= m; j++) {
        v.push_back(make_pair(i, j));
      }
    } else {
      for (int j = m; j >= 1; j--) {
        v.push_back(make_pair(i, j));
      }
    }
  }
  cout << n * m - 2 * (k - 1) << " ";
  for (int i = 0; i < n * m - 2 * (k - 1); i++) {
    cout << v[i].first;
    cout << " ";
    cout << v[i].second;
    cout << " ";
  }
  cout << endl;
  int a = n * m - 2 * (k - 1);
  for (int i = 0; i < k - 1; i++) {
    cout << 2 << " ";
    cout << v[a].first << " " << v[a].second << " ";
    a++;
    cout << v[a].first << " " << v[a].second << " ";
    a++;
    cout << endl;
  }
}
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  while (t--) {
    sol();
  }
  return 0;
}
