#include <bits/stdc++.h>
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;
int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(0);
  cin.exceptions(cin.failbit);
  int d, h, v, e;
  cin >> d >> h >> v >> e;
  double rate = v - ((3.14159265358979323846 * d * d * e) / 4);
  if (rate > 0) {
    printf("YES\n%lf\n", ((3.14159265358979323846 * d * d * h) / 4) / rate);
  } else {
    printf("NO\n");
  }
  return 0;
}
