program main
	implicit none
	integer    :: W, a, b
	read(*, *) W, a, b
	if(a <= b .AND. b <= a+W) then
		write(*, *) 0
	else if(a+W < b) then
		write(*, *) b-(a+W)
	else
		write(*, *) a-(b+W)
	end if
end program main