program main
    implicit none
    integer::n
    integer::a(100)
    integer::i,j,k,x,y,r,p,q,tmp

    read*,n

    a(1)=0
    a(2)=1
    do i=3,n
        x=xor(a(i/2),a(i-i/2))
        if(mod(i,3)==0.or.mod(i,3)==1)then
            y=a(i/3)
        else if(mod(i,3)==0)then
            y=a(i/3+1)
        end if
        if(x>=y)then
            x=tmp
            x=y
            y=tmp
        end if
        if(x/=0.and.y/=0)then
            a(i)=0
        else if(x/=1.and.y/=1)then
            a(i)=1
        else
            a(i)=2
        end if
    end do

    if(a(n)==0)then
        print*,"B"
    else
        print*,"A"
    end if


end program