program prob4
    integer::i,N
    character(len=200)::S,T
    character,allocatable::ans(:)
    read(*,*) N
    read(*,*) S, T
    allocate(ans(2*N))

    do i = 1,N
        ans(2*i-1) = S(i:i)
        ans(2*i) = T(i:i)
    end do

    write(*,*) ans

	deallocate(ans)
    stop
end program