#include<bits/stdc++.h>
#define rep(i, n) for (long long i = 0; i < (int)(n); i++)
#define put(i) cout<<fixed<<i<<endl
using namespace std;
using ll = long long;

int main(){
    ll n; cin >> n;
    vector<ll> a(n);
    ll sum = 0;
    rep(i,n) cin >> a[i];

    for(long long j = 0; j < n-1; j++){
        for(long long i = 0; i < n-j-1; i++){
            a[i] = (a[i] + a[i+1]) % 1000000007;
        }
    }
    put(a[0]);
}