program main
  
  implicit none
  integer :: n,i,j !859
  character(100) :: s, t
  character(200) :: new

  read(*,*) n 
  read(*,*) s, t 
  j = 0 
  do i = 1, 2*n 
    j = j + 1 
    new(j:j) = s(i:i) 
    j = j + 1 
    new(j:j) = t(i:i) 
  end do
  print*, new(1:2*n)
   
end program main
