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