#include <bits/stdc++.h>
using namespace std;
const int mx = 1e2 + 10;
const long long mod = 1e9 + 31;
mt19937 mtrand(time(0));
int n, m;
int main() {
  long long d, h, v, e;
  cin >> d >> h >> v >> e;
  if (4 * v <= e * acos(-1.0) * d * d)
    puts("NO");
  else {
    puts("YES");
    double r = d / 2.0;
    printf("%.12f\n", h / (v / (double)acos(-1.0) / r / r - e));
  }
}
