      program b159

      character*100 S
      integer A,B


      read(*,*)S

      A = len_trim(S)
      B = (A-1)/2
      if(S(1:B) == S(A-B+1:A)) then
        
      write(*,*)"Yes"
      else
      write(*,*)"No"
      endif


      end program b159


      