program problemA
  implicit none

integer :: K,A,B
integer :: n, m, yr,judge
character(len=4) :: S


read(*,*) S

if (S=='ABC') then
  write(*,*) 'ARC'
else
  write(*,*) 'ABC'
end if
! if (K==1) then
!   write(*,*) 'OK'
! else
!   if (A==B) then
!     if (mod(A,K)==0) then
!       write(*,*) 'OK'
!     else
!       write(*,*) 'NG'
!     end if
!   else
!     if (int(A/K)==int(B/K)) then
!       write(*,*) 'NG'
!     else
!       write(*,*) 'OK'
!     end if
!   end if
! end if



stop
end program
