#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(),x.end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
template<class T> inline bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T&a,T b){if(a>b){a=b;return 1;}return 0;}
using ll = long long;

ll n,mod=1e9+7;
ll a[110];

int main () {
    ios::sync_with_stdio(false); 
    cin.tie(0);

    cin >> n;
    rep(i,n) cin >> a[i];
    rep(i,n-1)rep(j,n-1-i) a[j]=(a[j]+a[j+1])%mod;
    cout << a[0] << endl;
}