#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, sx, sy;
  cin >> n >> m >> sx >> sy;
  cout << sx << " " << sy << "\n";
  for (int i = 1; i <= m; i++) {
    if (i == sy) continue;
    cout << sx << " " << i << "\n";
  }
  for (int i = 1, cnt = 1; i <= n; i++) {
    if (i == sx) continue;
    if (cnt & 1) {
      for (int j = m; j >= 1; j--) {
        cout << i << " " << j << "\n";
      }
    } else {
      for (int j = 1; j <= m; j++) {
        cout << i << " " << j << "\n";
      }
    }
    ++cnt;
  }
}
