func main()
	var n: int :: cui@inputInt()
	var a: []int :: #[n]int
	for i(0, n - 1)
		do a[i] :: cui@inputInt()
	end for
	
	for i(n - 1, 1, -1)
		var nx: []int :: #[i]int
		for j(0, i - 1)
			do nx[j] :: (a[j] + a[j + 1]) % (10 ^ 9 + 7)
		end for
		do a :: nx
	end for
	
	var ans: int :: a[0]
	do cui@print("\{ans}\n")
end func