import java.util.*;

public class Main {
    static final int N = 1010;
    static int[] a = new int[N], f = new int[N];

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        int n = Integer.parseInt(sc.nextLine());
        String[] s = sc.nextLine().split(" ");

        for (int i = 1; i <= n; i++) a[i] = Integer.parseInt(s[i - 1]);

        int ans = 0;
        for (int i = 1; i <= n; i++) {
            f[i] = a[i];//可能本身就是最大：a[i]=无穷大 当下面计算结果不会比a[i],则更新为a[i]
            for (int j = 1; j < i; j++) 
                if (a[i] > a[j]) f[i] = Math.max(f[i], f[j] + a[i]);
            ans = Math.max(f[i], ans);            
        }

        System.out.println(ans);
    }
}