#include <bits/stdc++.h>
using namespace std;
vector<vector<pair<int, int> > > res;
vector<int> s;
int main() {
  int n, m, k;
  scanf("%d%d%d", &n, &m, &k);
  for (int i = (0); i < (k - 1); ++i) s.push_back(2);
  s.push_back(n * m - (k - 1) * 2);
  int x = 0, y = 0;
  int dy = 1;
  int p = 0;
  int cnt = 0;
  res.resize(k);
  while (p < s.size()) {
    cnt++;
    res[p].push_back(make_pair(x + 1, y + 1));
    if (cnt == s[p]) {
      p++;
      cnt = 0;
    }
    y += dy;
    if (y >= m) {
      x++;
      y = m - 1;
      dy = -1;
    } else if (y < 0) {
      y = 0;
      x++;
      dy = 1;
    }
  }
  for (int i = (0); i < (k); ++i) {
    printf("%d", res[i].size());
    for (int j = (0); j < (res[i].size()); ++j) {
      printf(" %d %d", res[i][j].first, res[i][j].second);
    }
    printf("\n");
  }
  return 0;
}
