text: #include <iostream>
  #include <cstdio>
  #include <algorithm>
  #include <set>
  #include <string>
  #include <cmath>
  
  using namespace std;
  
  const double eps = 1e-9;
  const double PI = acos(-1);
  
  int main() {
    double d, h, v, e;
    cin >> d >> h >> v >> e;
  
    double ans = (h * PI * d * d / 4.) / (v - e * PI * d * d / 4);
    if (ans + eps < 0) {
      cout << "NO\n";
    } else {
      cout << "YES\n";
      printf("%.16lf\n", ans);
    }
    return 0;
  }
  