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