#include<iostream>
#include<cstdio>

using namespace std;

const int MAXN = 1000 + 10;

int arr[MAXN];

int dp[MAXN];   //备忘录数组

int main(){
	int n;
	while(scanf("%d",&n) != EOF){
		for(int i = 0; i < n; ++i){
			scanf("%d",&arr[i]);
		}
		int answer = 0;
		for(int i = 0; i < n; ++i){
			dp[i] = arr[i];
			for(int j = 0; j < i; ++j){
				if(arr[j] < arr[i]){
					dp[i] = max(dp[i],dp[j] + arr[i]);
				}
			}
			answer = max(answer,dp[i]);
		}
		printf("%d\n",answer);
	}
	return 0;
}