program main
  implicit none
  character*50::S
  integer::i,j,k,maxlen=1,slen,len
  read *, S
  slen = LEN_TRIM(S)
  do len = slen-1, 1, -1
     do j=1, slen - len + 1
!        print *, S(j:j+len-1), is_kaibun(S(j:j+len-1),len)
        if(is_kaibun( S(j:j+len-1), len)) then
           print '(i0)', len
           return
        end if
     end do
  end do
  print '(i0)', 1
contains
  function is_kaibun(S, len) result(l)
    logical::l
    character(*)::S
    integer::len,i
    do i=1, len/2
       if(S(i:i) .ne. S(len-i+1:len-i+1))then
          l = .false.
          return
       end if
    end do
    l = .true.
  end function is_kaibun
end program main