Problem: While sailing on a boat, Inessa noticed a beautiful water lily flower above the lake's surface. She came closer and it turned out that the lily was exactly H centimeters above the water surface. Inessa grabbed the flower and sailed the distance of L centimeters. Exactly at this point the flower touched the water surface.

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Suppose that the lily grows at some point A on the lake bottom, and its stem is always a straight segment with one endpoint at point A. Also suppose that initially the flower was exactly above the point A, i.e. its stem was vertical. Can you determine the depth of the lake at point A?

Input

The only line contains two integers H and L (1 ≤ H < L ≤ 10^{6}).

Output

Print a single number — the depth of the lake at point A. The absolute or relative error should not exceed 10^{-6}.

Formally, let your answer be A, and the jury's answer be B. Your answer is accepted if and only if \frac{|A - B|}{max{(1, |B|)}} ≤ 10^{-6}.

Examples

Input


1 2


Output


1.5000000000000


Input


3 5


Output


2.6666666666667

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
int MOD = 1e9 + 7;
const double EPS = 1e-9;
const int MAX_N = 2;
const int oo = INT_MAX;
const long long int OO = 1e18;
const int alldx[] = {1, 0, -1, 0, 1, -1, 1, -1};
const int alldy[] = {0, 1, 0, -1, 1, 1, -1, -1};
const int dx[] = {1, -1, 0, 0, 0, 0};
const int dy[] = {0, 0, 1, -1, 0, 0};
const int dz[] = {0, 0, 0, 0, 1, -1};
using namespace std;
long long int GCD(long long int a, long long int b) {
  return ((!b) ? a : GCD(b, a % b));
}
long long int LCM(long long int a, long long int b) {
  return a / (GCD(a, b)) * b;
}
long long int nCr(long long int n, long long int r) {
  if (n < r) return 0;
  if (r == 0) return 1;
  return n * nCr(n - 1, r - 1) / r;
}
long long int PowMod(long long int bs, long long int ex, long long int M) {
  if (!ex) return 1;
  long long int p = PowMod((bs * bs) % M, ex >> 1, M);
  return (ex & 1) ? (p * bs) % M : p;
}
long long int ModInverse(long long int a) { return PowMod(a, MOD - 2, MOD); }
long long int ExtGCD(long long int a, long long int b, long long int& x,
                     long long int& y) {
  if (!b) {
    x = 1;
    y = 0;
    return a;
  }
  long long int r = ExtGCD(b, a % b, y, x);
  y -= a / b * x;
  return r;
}
long long int mult(long long int a, long long int b) {
  return (1LL * a * b) % MOD;
}
bool isPrime(long long int n) {
  if (n == 2) return 1;
  if (n < 2 || n % 2 == 0) return 0;
  for (long long int i = 3; i * i <= n; i += 2)
    if (n % i == 0) return 0;
  return 1;
}
bool isPalindrome(string str) {
  long long int l = 0;
  long long int h = str.size() - 1;
  while (h > l) {
    if (str[l++] != str[h--]) {
      return 0;
    }
  }
  return 1;
}
long long int NoOfOdd(long long int L, long long int R) {
  long long int N = (R - L) / 2;
  if (R % 2 != 0 || L % 2 != 0) N++;
  return N;
}
long long int NoOfEven(long long int L, long long int R) {
  return ((R - L + 1) - NoOfOdd(L, R));
}
bool isPerfectSquare(long double x) {
  long double sr = sqrt(x);
  return ((sr - floor(sr)) == 0);
}
void GetAc() {
  long long int h, l;
  cin >> h >> l;
  long double ans = pow(l, 2);
  ans -= pow(h, 2);
  ans = (ans * 1.0);
  ans /= (2 * h);
  cout << fixed << setprecision(10) << (ans) << '\n';
}
int main() { GetAc(); }