#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const int N = 1e5 + 6;
const int inf = 0x3f3f3f3f;
const double PI = acos(-1.0);
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  d = d / 2;
  double ans = (PI * d * d * h) / (v - PI * d * d * e);
  if (PI * d * d * e > v)
    cout << "NO"
         << "\n";
  else {
    cout << "YES"
         << "\n";
    printf("%.10lf", ans);
  }
  return 0;
}
