#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, s1, s2;
  cin >> n >> m >> s1 >> s2;
  int x = s1;
  int y = s2;
  while (y <= m) {
    cout << x << " " << y << endl;
    y++;
  }
  y--;
  if (s2 != 1) {
    y = s2 - 1;
    while (y >= 1) {
      cout << x << " " << y << endl;
      y--;
    }
    y++;
  }
  if (x != 1) {
    x = x - 1;
    while (x >= 1) {
      if (y == 1) {
        while (y <= m) {
          cout << x << " " << y << endl;
          y++;
        }
        y--;
      } else {
        while (y >= 1) {
          cout << x << " " << y << endl;
          y--;
        }
        y++;
      }
      x--;
    }
    x++;
  }
  if (s1 != n) {
    x = s1 + 1;
    while (x <= n) {
      if (y == 1) {
        while (y <= m) {
          cout << x << " " << y << endl;
          y++;
        }
        y--;
      } else {
        while (y >= 1) {
          cout << x << " " << y << endl;
          y--;
        }
        y++;
      }
      x++;
    }
  }
}
