#include<bits/stdc++.h>
#include<algorithm>
using namespace std;
using ll=long long;

int main(){
    int n;
    cin >> n;
    ll Mod=1000000007;
    vector<ll> a(n);
    for(int i=0;i<n;i++){
        cin >> a[i];
    }
    for(int j=0;j<n-1;j++){
        for(int i=0;i<n-1-j;i++){
            a[i]=a[i]%Mod+a[i+1]%Mod;
        }
    }
    cout << a[0] << endl;
    return 0;
}