#include <bits/stdc++.h>
using namespace std;
vector<vector<int> > ans;
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  ans.resize(k + 1);
  int leng = 2;
  int j = 1;
  int d = -1;
  int cur = 1;
  if (k == 1) leng = n * m;
  for (int i = 1; i <= n; ++i) {
    if (d == 1)
      d = -1;
    else
      d = 1;
    while (1) {
      if (j > m) {
        j = m;
        break;
      }
      if (j < 1) {
        j = 1;
        break;
      }
      ans[cur].push_back(i);
      ans[cur].push_back(j);
      --leng;
      if (leng == 0) {
        if (cur == k - 1)
          leng = n * m;
        else
          leng = 2;
        ++cur;
      }
      j += d;
    }
  }
  for (int i = 1; i <= k; ++i) {
    cout << ans[i].size() / 2 << " ";
    for (int j = 0; j < ans[i].size(); ++j) cout << ans[i][j] << " ";
    cout << endl;
  }
  return 0;
}
