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
#    !/usr/bin/env python3
#    encoding: UTF-8
#    Modified: <30/Jul/2019 08:26:53 PM>


#    ✪ H4WK3yE乡
#    Mohd. Farhan Tahir
#    Indian Institute Of Information Technology (IIIT), Gwalior


import sys
import os
from io import IOBase, BytesIO


def main():
    h, l=get_ints()
    from math import atan2, pi, tan
    ang=atan2(l, h)
    #ang=ang*180/pi
    ang=pi-2*ang
    #print(ang)
    print(l/tan(ang))


BUFSIZE = 8192


class FastIO(BytesIO):
    newlines = 0

    def __init__(self, file):
         self._file = file
         self._fd = file.fileno()
         self.writable = "x" in file.mode or "w" in file.mode
         self.write = super(FastIO, self).write if self.writable else None

    def _fill(self):
         s = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
         self.seek((self.tell(), self.seek(0, 2), super(FastIO, self).write(s))[0])
         return s

    def read(self):
         while self._fill():
             pass
         return super(FastIO, self).read()

    def readline(self):
         while self.newlines == 0:
             s = self._fill()
             self.newlines = s.count(b"\n") + (not s)
         self.newlines -= 1
         return super(FastIO, self).readline()

    def flush(self):
         if self.writable:
             os.write(self._fd, self.getvalue())
             self.truncate(0), self.seek(0)


class IOWrapper(IOBase):
     def __init__(self, file):
         py2 = round(0.5)
         self.buffer = FastIO(file)
         self.flush = self.buffer.flush
         self.writable = self.buffer.writable
         if py2 == 1:
             self.write = self.buffer.write
             self.read = self.buffer.read
             self.readline = self.buffer.readline
         else:
             self.write = lambda s: self.buffer.write(s.encode("ascii"))
             self.read = lambda: self.buffer.read().decode("ascii")
             self.readline = lambda: self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)


def get_array(): return list(map(int, sys.stdin.readline().split()))


def get_ints(): return map(int, sys.stdin.readline().split())


def input(): return sys.stdin.readline().strip()


if __name__ == "__main__":
    main()
