#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, x, y;
  cin >> n >> m >> x >> y;
  for (int i = x; i > 1; i--) {
    cout << i << " " << y << endl;
  }
  cout << 2 << " " << y - 1 << endl;
  cout << 1 << " " << y - 1 << endl;
  for (int i = 3; i <= n; i++) {
    cout << i << " " << y - 1 << endl;
  }
  for (int i = y - 2; i > 0; i--) {
    for (int j = n; j > 0; j--) {
      if ((y - 2 - i) % 2) {
        cout << n - j + 1 << " " << i << endl;
      } else {
        cout << j << " " << i << endl;
      }
    }
  }
  if (y % 2 == 0) {
    for (int i = n; i > x; i--) {
      cout << i << " " << y << endl;
    }
    cout << 1 << " " << y << endl;
    for (int i = y + 1; i <= m; i++) {
      for (int j = 1; j <= n; j++) {
        if ((i - y + 1) % 2) {
          cout << n - j + 1 << " " << i << endl;
        } else {
          cout << j << " " << i << endl;
        }
      }
    }
  } else {
    cout << 1 << " " << y << endl;
    for (int i = x + 1; i <= n; i++) {
      cout << i << " " << y << endl;
    }
    for (int i = y + 1; i <= m; i++) {
      for (int j = 1; j <= n; j++) {
        if ((i - y + 1) % 2 == 0) {
          cout << n - j + 1 << " " << i << endl;
        } else {
          cout << j << " " << i << endl;
        }
      }
    }
  }
}
