#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  vector<vector<int>> chessboard(n, vector<int>(m));
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++) chessboard[i][j] = 0;
  cout << x << " " << y << endl;
  chessboard[x - 1][y - 1] = 1;
  if (chessboard[0][y - 1] == 0) cout << 1 << " " << y << endl;
  chessboard[0][y - 1] = 1;
  if (chessboard[0][0] == 0) cout << 1 << " " << 1 << endl;
  chessboard[0][0] = 1;
  int j = 0;
  for (int i = 0; i < n; i++) {
    if (j == m) j--;
    if (j < 0) j++;
    bool plus = (j == 0);
    while (j >= 0 && j < m) {
      if (chessboard[i][j] == 0) {
        cout << i + 1 << " " << j + 1 << endl;
        chessboard[i][j] = 1;
      }
      (plus) ? j++ : j--;
    }
  }
  return 0;
}
