import java.util.Scanner;

public class HelloWorld {
		public static void main (String[] args) {
			Scanner sc = new Scanner(System.in);
			int n = sc.nextInt();
			int[] ai = new int[n];
			long sum = 0;
			for (int i = 0; i < n; i ++) {
				ai[i] = sc.nextInt();
			}
			sc.close();

			for (int i = n-1; i > 1; i --) {
				for (int j = 0; j < i;j ++) {
					ai[j] = ai[j] + ai[j+1];
					ai[j] %= 1000000007;
				}
			}

			System.out.println((ai[0] + ai[1]) % 1000000007);

	}
}