#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, m, k;
  cin >> n >> m >> k;
  vector<vector<pair<int, int>>> ans(k);
  pair<int, int> p = {0, 0};
  for (int kk = 0; kk < k; ++kk) {
    bool ok = true;
    for (int i = p.first; i < n; ++i) {
      if (i % 2 == 0) {
        for (int j = p.second; j < m; ++j) {
          ans[kk].push_back({i, j});
          if (kk < k - 1 && ans[kk].size() == 2) {
            if (j == m - 1) {
              p = {i + 1, j};
            } else {
              p = {i, j + 1};
            }
            ok = false;
            break;
          }
        }
        if (!ok) break;
        p = {i + 1, m - 1};
      } else {
        for (int j = p.second; j >= 0; --j) {
          ans[kk].push_back({i, j});
          if (kk < k - 1 && ans[kk].size() == 2) {
            if (j == 0) {
              p = {i + 1, j};
            } else {
              p = {i, j - 1};
            }
            ok = false;
            break;
          }
        }
        if (!ok) break;
        p = {i + 1, 0};
      }
      if (p.first == n) break;
    }
  }
  for (int i = 0; i < k; ++i) {
    cout << ans[i].size();
    for (auto e : ans[i]) {
      cout << " " << e.first + 1 << " " << e.second + 1;
    }
    cout << '\n';
  }
}
int main(int argc, char* argv[]) {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  solve();
}
