package main

import . "fmt"

func main() {
	var n int
	Scan(&n)
	a:=make([]int,n)
	for i:=range a {
		Scan(&a[i])
	}
	const m = 1e9+7
	for ;n>1;n-- {
		for i,v:=range a[1:] {
			a[i]+=v
			a[i]%=m
		}
	}
	Println(a[0])
}