#include <iostream>
#include <fstream>

using namespace std;
ifstream f("date.in");
ofstream g("date.out");
int n,i,j,maxi;
int a[1000];
int main ()
{
    f>>n;
    for(i=1;i<=n;i++){
        f>>a[i];
    }
    for(i=1;i<=n;i++){
        for(j=i+1;j<=n;j++){
            a[i]=a[i]+a[j];
            if(a[i]>maxi) maxi=a[i];
        }
    }
    g<<maxi;
    return 0;
}