#include <bits/stdc++.h>
using namespace std;
const double pi = 3.14159265358979;
double d, h, v, e, otv;
int main() {
  cin >> d >> h >> v >> e;
  e = pi * (d / 2) * (d / 2) * e;
  if (e >= v) {
    cout << "NO";
  } else {
    cout << "YES" << endl;
    v = v - e;
    otv = pi * (d / 2) * (d / 2) * h;
    otv /= v;
    printf("%.13f", otv);
  }
}
