#include"iostream"

#include"stdio.h"

#include"string.h"

#include"algorithm"

#define mx 1010

using namespace std;

__int64 n;

__int64 value[mx];

__int64 dp[mx];

int main()

{

    __int64 i,j,ans;

    while(cin>>n,n)

    {

        for(i=;i<=n;i++)

            cin>>value[i];

        memset(dp,,sizeof(dp));

        value[]=;

        ans=;

        for(i=;i<=n;i++)

        {

            for(j=;j<i;j++)

            {

                if(value[j]<value[i])

                {

                    if(dp[j]+value[i]>dp[i]) dp[i]=dp[j]+value[i];

                    if(dp[i]>ans) ans=dp[i];

                }

            }

        }

        cout<<ans<<endl;

    }

    return ;

}