#include <bits/stdc++.h>
using namespace std;
long long int MOD = 1000000007;
long long int power(long long int x, long long int y, long long int p) {
  long long int res = 1;
  x = x % p;
  if (x == 0) return 0;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  ;
  long long int t;
  t = 1;
  while (t--) {
    long long int n, m, k;
    cin >> n >> m >> k;
    vector<long long int> xs, ys;
    for (long long int i = 0; i < n * m; i++) {
      ys.push_back(i / n + 1);
      if ((i / n) % 2 == 0) {
        xs.push_back(i % n + 1);
      } else {
        xs.push_back(n - i % n);
      }
    }
    for (long long int i = 0; i < k - 1; i++) {
      cout << 2 << ' ' << xs[2 * i] << ' ' << ys[2 * i] << ' ' << xs[2 * i + 1]
           << ' ' << ys[2 * i + 1] << endl;
    }
    cout << n * m - 2 * (k - 1) << ' ';
    for (long long int i = 2 * (k - 1); i < n * m; i++) {
      cout << xs[i] << ' ' << ys[i] << ' ';
    }
  }
}
