program tst1
	 integer n
	 real a(100)
	 real b(100)
	 print *, 'n = '
	 read *, n
	 read *, (a(i), i = 1, n)
	 do i=1,n/2
	   b(i)=2*a(2*i)
	 end do
	 print *, 'a '
	 print *, (a(i), i = 1, n)
	 print *, 'b '
	 print *, (b(i), i = 1, n/2)
	end program tst1