import strutils, sequtils, math

let
  tmp = map(split readLine stdin, parseInt)
  (a, b) = (tmp[0], tmp[1])
  r = max(a, b)
  x = min(a, b)

if a != b:
  echo sqrt(float(r ^ 2 - x ^ 2))
else:
  echo sqrt(float(2 * a ^ 2))