#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, sy, sx;
  cin >> n >> m >> sy >> sx;
  int up = sy;
  int down = sy + 1;
  int l = sx;
  int r = sx + 1;
  int k = 2;
  while (up >= 1) {
    while (l >= 1) {
      cout << up << " " << l << endl;
      l--;
    }
    while (r <= m) {
      cout << up << " " << r << endl;
      r++;
    }
    up--;
    if (k % 2 == 0)
      l = m;
    else
      r = 1;
    k++;
  }
  while (down <= n) {
    while (l >= 1) {
      cout << down << " " << l << endl;
      l--;
    }
    while (r <= m) {
      cout << down << " " << r << endl;
      r++;
    }
    down++;
    if (k % 2 == 0)
      l = m;
    else
      r = 1;
    k++;
  }
}
