#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9 + 7;
int N, M, K;
vector<int> vi, vj;
int main(void) {
  cin >> N >> M >> K;
  vector<int> v1, v2;
  for (int i = 1; i <= N; i++) v1.push_back(i), v2.push_back(N + 1 - i);
  for (int i = 0; i < (int)(N); ++i)
    for (int j = 0; j < (int)(M); ++j) {
      vi.push_back(i + 1);
      vj.push_back(i % 2 ? M - j : j + 1);
    }
  int id = 0;
  for (int i = 0; i < (int)(K - 1); ++i) {
    cout << 2 << " ";
    for (int j = 0; j < (int)(2); ++j)
      cout << vi[id] << " " << vj[id] << " ", id++;
    cout << endl;
  }
  cout << vi.size() - id << " ";
  while (id < (int)vi.size()) cout << vi[id] << " " << vj[id] << " ", id++;
  cout << endl;
  return 0;
}
