#include<iostream>
#include<algorithm>
using namespace std;
int n,w[5005],f[5005],i,j,ans=0;
int main()
{
scanf("%d",&n);
for(i=0;i<n;i++)scanf("%d",&w[i]);
for(i=0;i<n;i++){
f[i]=w[i];
for(j=0;j<i;j++)if(w[i]>w[j])f[i]=max(f[i],f[j]+w[i]);
ans=max(ans,f[i]);
}
printf("%d\n",ans);
return 0;
}