#include<bits/stdc++.h>
using namespace std;
using LL = long long;
using ULL = unsigned long long;
#define rep(i,n) for(int i=0; i<(n); i++)

int N;
int A[100];

int main() {
  cin>>N; rep(i,N) cin>>A[i];
  rep(i,N-1) rep(j,N-1) A[j]=(A[j]+A[j+1])%1000000007;
  cout<<A[0]<<endl;
  return 0;
}