program main
  implicit none
  real*4::a(2)
  read *,a
  if(a(1).eq.a(2)) then
     print '(f0.7)', sqrt(a(1)*a(1)+a(2)*a(2))
  else
     print '(f0.7)', sqrt(abs(a(1)*a(1)-a(2)*a(2)))
  end if
end program main