#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, x, y, i, j, temp1 = 0, temp2 = 0, temp3;
  cin >> n >> m;
  cin >> x >> y;
  cout << x << " " << y << endl;
  for (i = y - 1; i > 0; i--) {
    cout << x << " " << i << endl;
  }
  for (i = y + 1; i <= m; i++) {
    cout << x << " " << i << endl;
  }
  for (i = x - 1; i > 0; i--) {
    temp1++;
    for (j = 1; j <= m && temp1 % 2 == 0; j++) {
      cout << i << " " << j << endl;
    }
    for (j = m; j > 0 && temp1 % 2 != 0; j--) {
      cout << i << " " << j << endl;
    }
  }
  temp1 = j + 1;
  for (i = x + 1; i <= n; i++) {
    temp2++;
    for (j = 1; j <= m && temp2 % 2 != 0; j++) {
      if (temp1 == 1)
        cout << i << " " << j << endl;
      else
        cout << i << " " << m - j + 1 << endl;
    }
    for (j = m; j > 0 && temp2 % 2 == 0; j--) {
      if (temp1 == 1)
        cout << i << " " << j << endl;
      else
        cout << i << " " << m - j + 1 << endl;
    }
  }
  return 0;
}
