#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 9;
vector<long long> a(N);
long long ans[N];
int main() {
  long long n, m, k, i, j, ans = 0;
  cin >> n >> m >> k;
  vector<pair<long long, long long> > v[k + 1];
  bool ok = 1;
  long long s = 1;
  for (i = 1; i <= n; i++) {
    if (ok)
      for (j = 1; j <= m; j++) {
        if (s < k && v[s].size() == 2) s++;
        v[s].push_back({i, j});
      }
    else
      for (j = m; j >= 1; j--) {
        if (s < k && v[s].size() == 2) s++;
        v[s].push_back({i, j});
      }
    ok = 1 - ok;
  }
  for (i = 1; i <= k; i++) {
    cout << v[i].size() << ' ';
    for (auto x : v[i]) {
      cout << x.first << ' ' << x.second << ' ';
    }
    puts("");
  }
  return 0;
}
