using System;
using System.Linq;

namespace Problem1081
{
    class Program
    {
        static void Main(string[] args)
        {
            const long mod = 7 + (long)1e9;
            int N = GetInt();
            var A = GetLongArray();

            for(int i = 0; i < N - 1; i++)
            {
                var Anext = new long[A.Length - 1];
                for(int j = 0; j < Anext.Length; j++)
                {
                    Anext[j] = (A[j] + A[j + 1]) % mod;
                }
                A = Anext;
            }

            Console.WriteLine(A[0]);
        }

        public static int GetInt() => int.Parse(Console.ReadLine());
        public static int[] GetIntArray() => Console.ReadLine().Split().Select(int.Parse).ToArray();
        public static double GetDouble() => double.Parse(Console.ReadLine());
        public static double[] GetDoubleArray() => Console.ReadLine().Split().Select(double.Parse).ToArray();
        public static long GetLong() => long.Parse(Console.ReadLine());
        public static long[] GetLongArray() => Console.ReadLine().Split().Select(long.Parse).ToArray();

    }
}