#include <stdio.h>
#include <vector>


#define MOD (1000000007)

int main()
{
    std::vector<unsigned long> v;
    unsigned long n, in;
    scanf("%d", &n);
    
    for(int i = 0; i < n; i++)
    {
        scanf("%d", &in);
        v.push_back(in);
    }
    
    for(int i = n - 1; i > 0; i--)
    {
        for(int j = 0; j < i; j++)
        {
            v[j] = (v[j] + v[j + 1]) % MOD;
        }
    }
    
    printf("%d", v[0]);
    return 0;
}