#include <bits/stdc++.h>
using namespace std;
int main() {
  double a;
  double b, c, d;
  cin >> a;
  cin >> b >> c >> d;
  double bb;
  double r = a / 2;
  double kkk = r * r * 3.14159265358979323846264;
  double kraj = c / kkk;
  if (d >= kraj) {
    cout << "NO" << endl;
    return 0;
  } else {
    cout << "YES" << endl;
    double ggg = (b / (kraj - d));
    cout << fixed << setprecision(4);
    cout << ggg << endl;
  }
  return 0;
}
