#include <bits/stdc++.h>
using namespace std;
bool vis[500][500];
int n, m, k, x, c, idx, idy;
bool can(int i, int j) {
  if (i > n || i < 1 || j > m || j < 1 || vis[i][j]) return false;
  return true;
}
void DFS(int i, int j, int cell) {
  cout << i << " " << j << " ";
  vis[i][j] = true;
  if (cell == x) {
    idx = i, idy = j;
    return;
  }
  if (can(i, j + 1))
    DFS(i, j + 1, cell + 1);
  else if (can(i, j - 1))
    DFS(i, j - 1, cell + 1);
  else if (can(i + 1, j))
    DFS(i + 1, j, cell + 1);
}
inline int getid(void) {
  bool ok = 0;
  for (int i = 1; i <= n; i++) {
    if (i & 1) {
      for (int j = 1; j <= m; j++)
        if (!vis[i][j]) {
          idx = i, idy = j;
          ok = true;
          break;
        }
    } else {
      for (int j = m; j >= 1; j--)
        if (!vis[i][j]) {
          idx = i, idy = j;
          ok = true;
          break;
        }
    }
    if (ok) break;
  }
}
int main() {
  cin >> n >> m >> k;
  x = (m * n) - (2 * (k - 1));
  cout << x << " ";
  c++;
  DFS(1, 1, 1);
  cout << endl;
  bool ok = 0;
  x = 2;
  for (; c != k; c++) {
    cout << x << " ";
    if (can(idx, idy + 1))
      DFS(idx, idy + 1, 1);
    else if (can(idx, idy - 1))
      DFS(idx, idy - 1, 1);
    else if (can(idx + 1, idy))
      DFS(idx + 1, idy, 1);
    cout << endl;
  }
  return 0;
}
