program main

  implicit none
  integer :: i,j,n
  character(100) :: s, t
  character(200) :: st


  read(*,*) n
  read(*,*) s, t


  j = -1
  do i = 1, n
    j = j + 1
    st(j:j) = s(i:i)
    j = j + 1
    st(j:j) = t(i:i)
  end do

  write(6,"(1p,A)") st(0:2*n-1)

end program main