#include <bits/stdc++.h>
using namespace std;
long long GCD(long long a, long long b) { return (a) ? GCD(b % a, a) : b; }
long long LCM(long long a, long long b) { return a * b / GCD(a, b); }
double power(double a, long long b) {
  double x = 1;
  for (int i = 0; i < b; i++) {
    x = x * a;
  }
  return x;
}
int main() {
  float d, h, v, e;
  cin >> d >> h >> v >> e;
  float h2 = v * 1.0 / (atan(1) * power(d, 2));
  if (e >= h2) {
    cout << "NO" << endl;
    return 0;
  }
  float t = h * 1.0 / (h2 - e);
  cout << "YES" << endl;
  cout << t << endl;
  ;
  return 0;
}
