using System;

public class Hello
{
    public static void Main()
    {

        string line = System.Console.ReadLine().Trim();
        int N = int.Parse(line);

        line = System.Console.ReadLine().Trim();

        string[] Data = line.Split(' ');

        int t = 0;
        int p = 0;
        int q = 0;

        for (int i = 0; i < N; i++)
        {
            int vi =   int.Parse(Data[i]);

            t = q + vi;

            q = p > q ? p : q;

            p = t;            
        }
        System.Console.WriteLine(p>q?p:q);
    }
}