func main()
	var D: int :: cui@input().toInt(&)
	var a: []int :: #[D + 1]int
	var ss: [][]char :: cui@input().split(" ")
	for i(0, D)
		do a[i] :: ss[i].toInt(&)
	end for
	for i(D, 3, -1)
		do a[i - 2] :+ a[i]
	end for
	var d: int
	for i(2, 0, -1)
		if(a[i] <> 0)
			do d :: i
			break i
		end if
	end for
	do cui@print("\{d}\n")
	for i(0, d)
		do cui@print("\{a[i]}")
		do cui@print(i = d ?("\n", " "))
	end for
end func