#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  pair<int, int> c = make_pair(1, 0);
  int dx = 1, cover = 0, inc = 0;
  while (k != 1) {
    if (inc == 0) cout << 2 << " ";
    if (dx == 1 && c.second + dx <= m) {
      c.second += dx;
    } else if (dx == 1) {
      c.first++;
      dx = -1;
    } else if (dx == -1 && c.second + dx >= 1) {
      c.second += dx;
    } else if (dx == -1) {
      c.first++;
      dx = 1;
    }
    cout << c.first << " " << c.second << " ";
    inc++;
    if (inc == 2) {
      cout << endl;
      k--;
      inc = 0;
    }
    cover++;
  }
  cout << n * m - cover << " ";
  while (cover < n * m) {
    if (dx == 1 && c.second + dx <= m) {
      c.second += dx;
    } else if (dx == 1) {
      c.first++;
      dx = -1;
    } else if (dx == -1 && c.second + dx >= 1) {
      c.second += dx;
    } else if (dx == -1) {
      c.first++;
      dx = 1;
    }
    cout << c.first << " " << c.second << " ";
    cover++;
  }
  cout << endl;
  return 0;
}
