#include <bits/stdc++.h>
using namespace std;
const int N = 200000;
const int INF = (int)10e6;
const double eps = 10e-6;
const long long MOD = 1000000007;
vector<pair<int, int> > ans[100000];
int a[400][400];
int n, m, k;
int main() {
  std::ios::sync_with_stdio(false);
  cin >> n >> m >> k;
  int c = 1;
  for (int i = 1; i <= n; ++i) {
    if (i % 2 == 1) {
      if (m % 2 == 0) {
        for (int j = 1; j <= m; j += 2) {
          if (c == k + 1) {
            a[i][j] = k;
            a[i][j + 1] = k;
            ans[k].push_back(make_pair(i, j));
            ans[k].push_back(make_pair(i, j + 1));
          } else {
            a[i][j] = c;
            a[i][j + 1] = c;
            ans[c].push_back(make_pair(i, j));
            ans[c].push_back(make_pair(i, j + 1));
            c++;
          }
        }
      } else {
        for (int j = 1; j < m; j += 2) {
          if (c == k + 1) {
            a[i][j] = k;
            a[i][j + 1] = k;
            ans[k].push_back(make_pair(i, j));
            ans[k].push_back(make_pair(i, j + 1));
          } else {
            a[i][j] = c;
            a[i][j + 1] = c;
            ans[c].push_back(make_pair(i, j));
            ans[c].push_back(make_pair(i, j + 1));
            c++;
          }
        }
        if (c <= k) {
          a[i][m] = c;
          ans[c].push_back(make_pair(i, m));
          if (i + 1 <= n) {
            a[i + 1][m] = c;
            ans[c].push_back(make_pair(i + 1, m));
            c++;
          }
        } else {
          a[i][m] = k;
          ans[k].push_back(make_pair(i, m));
          if (i + 1 <= n) {
            a[i + 1][m] = k;
            ans[k].push_back(make_pair(i + 1, m));
          }
        }
      }
    } else {
      if (m % 2 == 0) {
        for (int j = m; j >= 1; j -= 2) {
          if (c == k + 1) {
            a[i][j] = k;
            a[i][j - 1] = k;
            ans[k].push_back(make_pair(i, j));
            ans[k].push_back(make_pair(i, j - 1));
          } else {
            a[i][j] = c;
            a[i][j - 1] = c;
            ans[c].push_back(make_pair(i, j));
            ans[c].push_back(make_pair(i, j - 1));
            c++;
          }
        }
      } else {
        for (int j = m - 1; j >= 1; j -= 2) {
          if (c == k + 1) {
            a[i][j] = k;
            a[i][j - 1] = k;
            ans[k].push_back(make_pair(i, j));
            ans[k].push_back(make_pair(i, j - 1));
          } else {
            a[i][j] = c;
            a[i][j - 1] = c;
            ans[c].push_back(make_pair(i, j));
            ans[c].push_back(make_pair(i, j - 1));
            c++;
          }
        }
      }
    }
  }
  for (int i = 1; i <= k; ++i) {
    cout << ans[i].size() << " ";
    for (int j = 0; j < ans[i].size(); ++j) {
      int x = ans[i][j].first;
      int y = ans[i][j].second;
      cout << ans[i][j].first << " " << ans[i][j].second << " ";
    }
    cout << "\n";
  }
  return 0;
}
