#include <bits/stdc++.h>
using namespace std;
void wldd() {
  long long n, m, x, y;
  cin >> n >> m >> x >> y;
  cout << x << " " << y << "\n";
  for (long long i = 1; i <= n; i++) {
    if (i != x) cout << i << " " << y << "\n";
  }
  long long a = 1;
  for (long long i = 1; i <= m; i++) {
    if (i == y) continue;
    if (a == 1) {
      cout << n << " " << i << "\n";
      for (long long j = n - 1; j >= 1; j--) {
        cout << j << " " << i << "\n";
      }
      a = 0;
    } else {
      cout << 1 << " " << i << "\n";
      for (long long j = 2; j <= n; j++) {
        cout << j << " " << i << "\n";
      }
      a = 1;
    }
  }
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  wldd();
  return 0;
}
