#include <bits/stdc++.h>
using namespace std;
int R, C, K;
vector<pair<int, int> > ord;
int main() {
  cin >> R >> C >> K;
  for (int i = 1; i <= R; i++) {
    if (i % 2) {
      for (int j = 1; j <= C; j++) ord.push_back(pair<int, int>(i, j));
    } else {
      for (int j = C; j >= 1; j--) ord.push_back(pair<int, int>(i, j));
    }
  }
  int cur = 0;
  for (int i = 1; i <= K - 1; i++) {
    printf("2 %d %d %d %d\n", ord[cur].first, ord[cur].second,
           ord[cur + 1].first, ord[cur + 1].second);
    cur += 2;
  }
  printf("%d", R * C - cur);
  for (; cur < R * C; cur++) printf(" %d %d", ord[cur].first, ord[cur].second);
  printf("\n");
}
