#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/stack:200000000")
int t, n, m, j, ans, k, a, b, c, d, e, f, sum, i, sz, row, col, l;
string s, s2, s3, s4;
deque<pair<int, int> > v;
void brainfuck();
int main() {
  ios_base::sync_with_stdio(NULL);
  cin.tie(NULL);
  cout.tie(NULL);
  brainfuck();
  return 0;
}
void brainfuck() {
  cin >> n >> m >> k;
  for (i = 1; i <= n; i++) {
    for (j = 1; i & 1 && j <= m; j++) v.push_back({i, j});
    for (j = m; i % 2 == 0 && j >= 1; j--) v.push_back({i, j});
  }
  for (j = 1; j <= k; j++) {
    if (j != k)
      a = 2;
    else
      a = v.size();
    cout << a;
    while (a--) {
      cout << " " << v.front().first << " " << v.front().second;
      v.pop_front();
    }
    cout << "\n";
  }
}
