#include<bits/stdc++.h>
#define REP(i,n) for(int i=0,i##_len=int(n);i<i##_len;++i)
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
#define All(x) (x).begin(),(x).end()
#define rAll(x) (x).rbegin(),(x).rend()
using namespace std;
using ll = long long;

int main(){
    int N;cin>>N;
    vector<int> A(N);
    constexpr int mod = 1e9+7;
    REP(i,N) cin>>A[i];
    REP(i,N-1) {
        vector<int> B(N-i-1);
        REP(j,N-i-1){
            B[j] = A[j] + A[j+1];
            B[j] %= mod;
        }
        A=B;
    }
    cout<<A[0]<<endl;
}