#include <iostream>
using namespace std;
int main()
{
long double n;
cin>>n;
long double suma=0;
long double makskasa=0;
long double c;
while (n--)
{
cin >>c;
suma+=c;
if (makskasa<suma)
{
makskasa=suma;
}
if (0>suma)
{
suma=0;
}
}
cout<<makskasa << endl ;
return 0;
}
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