program test
implicit none

integer(8) :: x
real(8) :: ans,p

read(*,*) x
read(*,*) p

if(p == 100) then
	if(mod(x,2) == 0)then
		ans = x/2.
	else
		ans = (x-1)/2. + 1.
	endif
else
	if(mod(x,2) == 0)then
		ans = (x/2.) * (100./p)
	else if(x == 1) then
		ans = 1. + 100./p
	else
		ans = 1. + (p/100.) * ((x-1.)/2.) * (100./p) + (1.-p/100.) * ((x+1.)/2.) * (100./p)
	endif
endif


write(*,*) ans

end program