program main
      implicit none
      integer :: n, i
      character(100) :: s, t
      character(200) :: ans

      read *, n
      read *, s, t

      n = len_trim(s)

      do i = 1, n
        ans(2*(i-1)+1:2*(i-1)+1) =  s(i:i)
        ans(2*i:2*i) =  t(i:i)
      end do

      print *, ans(1:2*n)

end program main
