#include <bits/stdc++.h>
using namespace std;
vector<pair<int, int> > re[90000];
void dfs(int n, int m, int k) {
  int posx = 0;
  int posy = 0;
  int mark = 1;
  int c = 0;
  while (posx >= 0 && posx < n && posy >= 0 && posy < m) {
    re[mark].push_back(pair<int, int>(posx, posy));
    c++;
    if (c == 2 && mark != k) {
      mark++;
      c = 0;
    }
    if (posx % 2 == 0) {
      posy++;
      if (posy == m) {
        posx++;
        posy = m - 1;
      }
    } else {
      posy--;
      if (posy == -1) {
        posx++;
        posy = 0;
      }
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m, k;
  cin >> n >> m >> k;
  dfs(n, m, k);
  for (int i = 1; i <= k; i++) {
    cout << re[i].size() << " ";
    for (int(j) = 0; (j) < (int)(re[i].size()); (j)++) {
      cout << re[i][j].first + 1 << " " << re[i][j].second + 1 << " ";
    }
    cout << '\n';
  }
}
