#include <bits/stdc++.h>
long long int pow1(long long int, long long int);
using namespace std;
int main() {
  int n, m, k, i, j, visited[305][305], count;
  vector<pair<int, int> > vec;
  cin >> n >> m >> k;
  for (i = 0; i < n + 1; ++i)
    for (j = 0; j < m + 1; ++j) visited[i][j] = 0;
  for (i = 1; i < m + 1; ++i) {
    visited[0][i] = 1;
    visited[n + 1][i] = 1;
  }
  for (i = 1; i < n + 1; ++i) {
    visited[i][0] = 1;
    visited[i][m + 1] = 1;
  }
  i = 1;
  j = 1;
  count = 1;
  visited[i][j] = 1;
  vec.push_back(make_pair(i, j));
  while (count < n * m) {
    if (visited[i][j + 1] == 0) {
      vec.push_back(make_pair(i, j + 1));
      visited[i][j + 1] = 1;
      j++;
    } else if (visited[i][j - 1] == 0) {
      vec.push_back(make_pair(i, j - 1));
      visited[i][j - 1] = 1;
      j--;
    } else {
      vec.push_back(make_pair(i + 1, j));
      visited[i + 1][j] = 1;
      i++;
    }
    count++;
  }
  for (i = 0; i < k - 1; ++i) {
    cout << 2 << " " << vec[2 * i].first << " " << vec[2 * i].second << " ";
    cout << vec[2 * i + 1].first << " " << vec[2 * i + 1].second << endl;
  }
  cout << n * m - 2 * (k - 1) << " ";
  for (i = 2 * (k - 1); i < n * m; ++i) {
    cout << vec[i].first << " " << vec[i].second << " ";
  }
  cout << endl;
  return 0;
}
long long int pow1(long long int a, long long int b) {
  long long int ans = 1;
  while (b) {
    if (b & 1) {
      ans = ans * a;
    }
    a = a * a;
    b = b >> 1;
  }
  return ans;
}
