import java.io.*;
import java.util.*;

public class Main {
    static final int MOD = 1000000007;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int[] current = new int[n];
        for (int i = 0; i < n; i++) {
            current[i] = sc.nextInt();
        }
        for (int i = 0; i < n - 1; i++) {
            int[] next = new int[n - i - 1];
            for (int j = 0; j < n - i - 1; j++) {
                next[j] = (current[j] + current[j + 1]) % MOD;
            }
            current = next;
        }
        System.out.println(current[0]);
    }
}
    
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}