#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-8;
const double pi = acos(-1.0);
int sig(double x) { return (x > eps) - (x < -eps); }
int d, h, e, v;
int main() {
  cin >> d >> h >> v >> e;
  double area = pi * 0.25 * d * d;
  double vol = area * h;
  double dec_v = area * e;
  if (sig(v * 1. - dec_v) <= 0)
    puts("NO");
  else {
    double x = vol / (v * 1. - dec_v);
    printf("YES\n%.10f\n", x);
  }
  return 0;
}
