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