#include <iostream>
using namespace std;
int arr[1001];
int D[1001];
int main(){
int N;
cin>>N;
for (int i=0; i<N; i++) cin>>arr[i];
int ans=0;
for (int i=0; i<N; i++){
D[i] = arr[i];
for (int j=0; j<i; j++){
int tmp=0;
if(D[j]<D[i]) D[i] = max(D[i], D[j]+arr[i]);
}
ans=max(ans, D[i]);
}
cout<<ans;
}