#include <bits/stdc++.h>
using namespace std;
long long powmod(long long a, long long p, long long m) {
  long long r = 1;
  while (p) {
    if (p & 1) r = r * a % m;
    p >>= 1;
    a = a * a % m;
  }
  return r;
}
const int MaxN = 1e5 + 55;
const long long INF = 1e10 + 10;
const long long MOD = 1e9 + 7;
int d, h, v, e;
double PI = 3.14159265, r2;
int main() {
  cin >> d >> h >> v >> e;
  r2 = ((double)(d) / 2) * ((double)(d) / 2);
  double vR = e * PI * r2;
  if (vR > v)
    cout << "NO";
  else {
    cout << "YES" << '\n';
    double x = (v - vR) / (PI * r2);
    cout << fixed << setprecision(6) << (double)h / x;
  }
}
