#include <iostream>
#include <algorithm>
#include <stdio.h>
using namespace std;
int main(void){
	cin.tie(NULL);
	ios::sync_with_stdio(false);
	int N;
	cin>>N;
	int arr[N+1] = {0};
	int dp[N+1] = {0};
	for(int i=1;i<=N;i++)
		cin>>arr[i];
	dp[1] = 1;
	int mmax = 1;
	for(int i=2;i<=N;i++){
		int cnt = 0;
		for(int j=1;j<i;j++){
			if(arr[i] > arr[j]){
				if(cnt < dp[j])
					cnt = dp[j];
			}
			dp[i] = cnt+1;
			if(mmax < dp[i])
				mmax = dp[i];
		}
	} // 14002와 11053 풀때 썼던 dp
	int arr_sum[N+1]={0}; //합을 저장하는 배열
	for(int i=1;i<=N;i++){
		int max_sum=0;
		for(int j=0;j<i;j++){
			if(dp[j] == dp[i]-1 && arr[j] < arr[i]){
				int temp = arr_sum[j];
				max_sum = max(max_sum,temp);
			} // dp가 1작고 arr[i]보다 작은 수의 arr_sum[j]중에 큰값을 max_sum에 저장
		}
		arr_sum[i] = arr[i] + max_sum; // arr_sum[i] 구하기
	}
	int result=0;
	for(int i=1;i<=N;i++)
		result = max(result,arr_sum[i]); // 한번 쭉 돌면서 제일 큰 값출력
	cout<<result<<endl;
}

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