#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(LL i = a;i<b; i++)
#define rrep(i,a,b) for(LL i = a;i>b; i--)
#define tobirep(i,a,b,c) for(LL i = a;i<b; i+=c)
#define tobirrep(i,a,b,c) for(LL i = a;i>b; i-=c)
#define INF ((1LL<<62)-(1LL<<31))
#define ooki 9223372036854775807
#define tii -9223372036854775808
typedef long long LL;
int main(){
 LL n,mod=1000000007;
  cin >> n;
  vector<LL> a(n);
  rep(i,0,n){cin >> a[i];}
  rep(i,0,n-1){
   rep(j,0,n-1){
    a[j]=(a[j]+a[j+1])%mod;
   }
  }
  cout << a[0] << endl;
}