program sample
	implicit none
    integer :: x,a,b,c,d
    
    read(*,*) x,a,b
    
    c=abs(x-a)
    d=abs(x-b)
    
    if (c>d) then
    	write(*,*) 'B'
    else
    	write(*,*) 'A'
    end if
    
    stop
end program sample