BAEKJOON_11052_DP

import java.io.*;
import java.sql.Array;
import java.util.*;


public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int N = Integer.parseInt(br.readLine());
        int[] p = new int[N+1];
        int[] dp = new int[N+1];
        p[0]=0;
        dp[0]=0;

        StringTokenizer st = new StringTokenizer(br.readLine());

        for(int i=1; i<N+1; i++){
            p[i] = Integer.parseInt(st.nextToken());
        }

        for(int i=1; i<=N; i++) {
            for (int j = 1; j <= i; j++) {
                dp[i] = Math.max(dp[i],p[j] + dp[i - j]);
            }
        }

        bw.write(String.valueOf(dp[N]));
        bw.flush();
        bw.close();
    } 
}