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