using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Numerics;

namespace AtCoderWorkspace
{
    public class Solver
    {
        public void Solve()
        {
            var cin = new Scanner();
            var n = cin.nextInt();
            var a = cin.ArrayLong(n);

            var acc = new long[n + 1];
            acc[0] = 0;
            for (int i = 1; i <= n; i++)
            {
                acc[i] = acc[i - 1] + a[i-1];
            }

            long pv = 0;
            long abs = long.MaxValue;
            for (int i = 0; i <= n; i++)
            {
                var leftwa = query(acc, 0, i);
                var rightwa = query(acc, i, n);
                
                if(abs < Math.Abs(leftwa - rightwa))
                {
                    var left = query(acc, 0, i-1);
                    var right = query(acc, i-1, n);
                    Console.WriteLine(Math.Abs(left - right));
                    return;
                }

                abs = Math.Abs(leftwa - rightwa);
            }           
        }

        public long query(long[] acc, long left, long right)
        {
            return acc[right] - acc[left];
        }
    }

    class Scanner
    {
        string[] s;
        int i;

        char[] cs = new char[] { ' ' };

        public Scanner()
        {
            s = new string[0];
            i = 0;
        }

        public string next()
        {
            if (i < s.Length) return s[i++];
            string st = Console.ReadLine();
            while (st == "") st = Console.ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            if (s.Length == 0) return next();
            i = 0;
            return s[i++];
        }

        public int nextInt()
        {
            return int.Parse(next());
        }
        public int[] ArrayInt(int N, int add = 0)
        {
            int[] Array = new int[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt() + add;
            }
            return Array;
        }

        public int[] DPArrayInt(int N, int ex)
        {
            int[] Array = new int[N+ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextInt();
            }
            return Array;
        }

        public long nextLong()
        {
            return long.Parse(next());
        }

        public long[] ArrayLong(int N, long add = 0)
        {
            long[] Array = new long[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong() + add;
            }
            return Array;
        }

        public long[] DPArrayLong(int N, int ex)
        {
            long[] Array = new long[N + ex];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextLong();
            }
            return Array;
        }

        public double nextDouble()
        {
            return double.Parse(next());
        }


        public double[] ArrayDouble(int N, double add = 0)
        {
            double[] Array = new double[N];
            for (int i = 0; i < N; i++)
            {
                Array[i] = nextDouble() + add;
            }
            return Array;
        }
    }   

    class Program
    {
        static void Main(string[] s) => new Solver().Solve();
    }
}


Measured memory_bytes: 36944