#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, x, y, posx, posy, k = 0;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << endl;
  for (int j = y + 1; j <= m; j++) {
    posx = x;
    posy = j;
    cout << posx << " " << posy << endl;
  }
  for (int j = y - 1; j > 0; j--) {
    posx = x;
    posy = j;
    cout << posx << " " << posy << endl;
  }
  for (int i = x + 1; i <= n; i++) {
    if (k % 2 == 0) {
      for (int j = 1; j <= m; j++) {
        posx = i;
        posy = j;
        cout << posx << " " << posy << endl;
      }
      k++;
    } else {
      for (int j = m; j > 0; j--) {
        posx = i;
        posy = j;
        cout << posx << " " << posy << endl;
      }
      k++;
    }
  }
  k = 0;
  if (posy == 1) {
    for (int i = x - 1; i > 0; i--) {
      if (k % 2 == 0) {
        for (int j = 1; j <= m; j++) {
          posx = i;
          posy = j;
          cout << posx << " " << posy << endl;
        }
        k++;
      } else {
        for (int j = m; j > 0; j--) {
          posx = i;
          posy = j;
          cout << posx << " " << posy << endl;
        }
        k++;
      }
    }
  } else {
    for (int i = x - 1; i > 0; i--) {
      if (k % 2 != 0) {
        for (int j = 1; j <= m; j++) {
          posx = i;
          posy = j;
          cout << posx << " " << posy << endl;
        }
        k++;
      } else {
        for (int j = m; j > 0; j--) {
          posx = i;
          posy = j;
          cout << posx << " " << posy << endl;
        }
        k++;
      }
    }
  }
  return 0;
}
