#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
const double eps = 1e-8;
template <class T>
T abs(T a) {
  return a >= 0 ? a : -a;
}
template <class T>
T sqr(T a) {
  return a * a;
}
template <class T>
T gcd(T a, T b) {
  return b ? gcd(b, a % b) : a;
}
template <class T>
T mod(T a, T b) {
  return (a % b + b) % b;
}
template <class T>
T addmod(T a, T b, T c) {
  return (T)mod((long long)a + b, (long long)c);
}
template <class T>
T mulmod(T a, T b, T c) {
  return (T)mod((long long)a * b, (long long)c);
}
template <class T>
T powmod(T a, T b, T c) {
  return (T)mod(
      b ? mulmod(mod(sqr((long long)powmod(a, b >> 1, c)), (long long)c),
                 (b & 1LL) ? a : 1LL, (long long)c)
        : 1LL,
      (long long)c);
}
template <class T>
void maxe(T &a, T b) {
  a = max(a, b);
}
template <class T>
void mine(T &a, T b) {
  a = min(a, b);
}
template <class T>
void mode(T &a, T b) {
  a = mod(a, b);
}
template <class T>
void addmode(T &a, T b, T c) {
  a = addmod(a, b, c);
}
template <class T>
void mulmode(T &a, T b, T c) {
  a = mulmod(a, b, c);
}
template <class T>
void powmode(T &a, T b, T c) {
  a = powmod(a, b, c);
}
int iszero(double a) { return abs(a) <= eps; }
template <class T>
void geti(T &a) {
  a = 0;
  long long b = 1;
  char c = getchar();
  if (c == '-')
    b = -1;
  else
    a = c - 48;
  while ((c = getchar()) != ' ' && c != '\n') a = a * 10 + c - 48;
  a *= b;
}
void fileio_in_out() {
  freopen(".in", "r", stdin);
  freopen(".out", "w", stdout);
}
void fileio_txt() {
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
double a, v, l, d, w;
double cal(double u, double dis) {
  double vl = sqrt(u * u + 2 * a * dis);
  double t = 0;
  if (vl > v + eps) {
    t = (v - u) / a;
    double di = u * t + 0.5 * a * t * t;
    di = dis - di;
    t = t + (di / v);
  } else {
    t = (vl - u) / a;
  }
  return t;
}
int main() {
  cin >> a >> v;
  cin >> l >> d >> w;
  double vd = sqrt(2 * a * d);
  if (v > w + eps && vd > w + eps) {
    double dl = (w * w + 2 * a * d);
    dl = dl / (4 * a);
    double vdl = sqrt(2 * a * dl);
    if (v > vdl + eps) {
      double t = sqrt(2 * dl / a);
      t = t + (vdl - w) / a;
      t = t + cal(w, l - d);
      printf("%.10lf\n", t);
    } else if (vdl > v + eps) {
      double ttop = v / a;
      double dtop = 0.5 * a * ttop * ttop;
      double dleft = d - dtop;
      double dstop = (v * v - w * w) / (2 * a);
      double tsame = (dleft - dstop) / v;
      double tless = (v - w) / a;
      double t = ttop + tsame + tless + cal(w, l - d);
      printf("%.10lf\n", t);
    }
  } else {
    printf("%.10lf\n", cal(0, l));
  }
  return 0;
}
