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