#include <bits/stdc++.h>
using namespace std;
int main(int argc, const char* argv[]) {
  int r, c, k, cells, dir = 1, counter = 1, curr = 0;
  int per;
  cin >> r >> c >> k;
  vector<vector<pair<int, int> > > V(k + 50, vector<pair<int, int> >(0));
  cells = r * c;
  per = cells / k;
  for (int i = 0; i < r; i++) {
    for (int j = (dir == 1 ? 0 : c - 1); j >= 0 && j < c; j += dir) {
      if (curr == per && counter != k) {
        counter++;
        curr = 1;
      } else
        curr++;
      V[counter].push_back(make_pair(i, j));
    }
    if (dir == 1)
      dir = -1;
    else
      dir = 1;
  }
  for (int i = 1; i <= k; i++) {
    cout << V[i].size() << " ";
    for (int j = 0; j < V[i].size(); j++) {
      cout << V[i][j].first + 1 << " " << V[i][j].second + 1;
      if (j != V[i].size() - 1) cout << " ";
    }
    cout << endl;
  }
  return 0;
}
