#include <bits/stdc++.h>
using namespace std;
const int INF = numeric_limits<int>::max();
const long long LINF = numeric_limits<long long>::max();
const double eps = 1e-10;
const int MOD = 1e9 + 7;
const int MAXN = 1e6 + 6;
int a[MAXN];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double rain = acos(-1.) * d * d / 4 * e;
  if (rain >= v) {
    cout << "NO";
    return 0;
  }
  double sw = acos(-1.) * d * d / 4 * h;
  double ans = sw / (v - rain);
  cout << "YES\n";
  cout << fixed << setprecision(9) << ans;
  return 0;
}
