//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int siz(string s){
  return (int)s.size();
}

int main(){
  int N; cin >> N;
  vector<vector<ll>> X(N, vector<ll>(N, 0));
  for(int i = 0; i < N; i++) cin >> X[0][i];

  for(int i = 1; i < N; i++){
    for(int j = 0; i+j < N; j++){
      ll sum = X[i-1][j] + X[i-1][j+1];

      X[i][j] = sum%1000000007;
    }
  }

  printl(X[N-1][0]);

  return 0;
}