#include <bits/stdc++.h>
using namespace std;
const int MX = (int)1e6 + 17;
const int MOD = (int)1e9 + 7;
const long long oo = (long long)1e18 + 7;
const int INF = (int)999999999;
const int N = (int)1e5 + 17;
const int di[4] = {-1, 0, 1, 0};
const int dj[4] = {0, 1, 0, -1};
inline long long IN() {
  long long x = 0, ch = getchar(), f = 1;
  while (!isdigit(ch) && (ch != '-') && (ch != EOF)) ch = getchar();
  if (ch == '-') {
    f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = (x << 1) + (x << 3) + ch - '0';
    ch = getchar();
  }
  return x * f;
}
inline void OUT(long long x) {
  if (x < 0) putchar('-'), x = -x;
  if (x >= 10)
    OUT(x / 10), putchar(x % 10 + '0');
  else
    putchar(x + '0');
}
double d, h, v, e, ans;
int main() {
  cin >> d >> h >> v >> e;
  ans = e - ((4 * v) /
             (3.14159265358979323846264338327950288419716939937510 * d * d));
  h = -h;
  if (ans > -1e4 && ans < 0)
    cout << "YES" << endl << fixed << setprecision(10) << (h / ans);
  else
    cout << "NO";
  return 0;
}
