#include <bits/stdc++.h>
using namespace std;
double d, h, v, e;
bool empty(double t) {
  double bal = h * d * d * acos(-1) + t * e * d * d * acos(-1);
  bal -= t * v;
  return bal <= 0;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> d >> h >> v >> e;
  d /= 2;
  double high = 10000;
  double low = 0;
  if (!empty(10000)) {
    cout << "NO";
    return 0;
  }
  printf("YES\n");
  while (high - low > 1e-8) {
    double mid = (low + high) / 2;
    if (empty(mid))
      high = mid;
    else
      low = mid;
  }
  printf("%0.12lf\n", low);
  return 0;
}
