#include<bits/stdc++.h>

using namespace std;
using ll=long long;
#define rep2(i, a, n) for(int i = (a); i < (n); i++)
#define rep(i, n) rep2(i,0,n)
#define mod 1000000007

int main(){
  cin.tie(nullptr);ios_base::sync_with_stdio(false);
  int n;
  cin>>n;
  ll a[n];
  rep(i,n)cin>>a[i];
  rep(i,n-1){
    rep(j,n-i-1){
      a[j]+=a[j+1]%mod;
    }
  }
  cout<<a[0]<<endl;
}