Problem:
Score : 300 points

Problem Statement

Snuke and Raccoon have a heap of N cards. The i-th card from the top has the integer a_i written on it.

They will share these cards.
First, Snuke will take some number of cards from the top of the heap, then Raccoon will take all the remaining cards.
Here, both Snuke and Raccoon have to take at least one card.

Let the sum of the integers on Snuke's cards and Raccoon's cards be x and y, respectively.
They would like to minimize |x-y|.
Find the minimum possible value of |x-y|.

Constraints

2 \leq N \leq 2 \times 10^5

-10^{9} \leq a_i \leq 10^{9}

a_i is an integer.

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_{N}

Output

Print the answer.

Sample Input 1

6
1 2 3 4 5 6

Sample Output 1

1

If Snuke takes four cards from the top, and Raccoon takes the remaining two cards, x=10, y=11, and thus |x-y|=1. This is the minimum possible value.

Sample Input 2

2
10 -10

Sample Output 2

20

Snuke can only take one card from the top, and Raccoon can only take the remaining one card. In this case, x=10, y=-10, and thus |x-y|=20.

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

#pragma warning disable

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Serialization.Formatters.Binary;
using System.Text;
using System.Text.RegularExpressions;
using System.Diagnostics;
using System.Numerics;
using System.Collections;
using System.Timers;
using System.Threading;
// using System.Threading.Tasks;

static class MainClass
{
    public static void Main(string[] args)
    {
        var N = Console.ReadLine().ToInt32();
        var an = Console.ReadLine().SplittedStringToInt32List();
        long x = 0;
        long y = 0;
        if (N == 2)
        {
            Console.WriteLine(Math.Abs(an[0] - an[1]));
        }
        else
        {
            var queue = new Queue<int>(an.OrderByDescending(_ => _).ToList());
            while (queue.Count > 0)
            {
                var item = queue.Dequeue();
                if (x > y)
                {
                    y += item;
                }
                else
                {
                    x += item;
                }
            }
            Console.WriteLine(Math.Abs(x - y));
        }

        Console.ReadLine();
    }
    

    #region ライブラリ

    #region 文字列処理

    public static int ToInt32(this string str) => int.Parse(str);
    public static BigInteger ToBigInteger(this string str) => BigInteger.Parse(str);
    public static List<string> SplittedStringToList(this string str) => str.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).ToList();
    public static List<int> SplittedStringToInt32List(this string str) => str.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(x => int.Parse(x)).ToList();

    public static List<BigInteger> SplittedStringToBigInteger(this string str) => str.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).Select(x => BigInteger.Parse(x)).ToList();
    #endregion
    #region DeepClone
    public static T DeepClone<T>(this T src)
    {
        using (var memoryStream = new MemoryStream())
        {
            var binaryFormatter
              = new BinaryFormatter();
            binaryFormatter.Serialize(memoryStream, src);
            memoryStream.Seek(0, SeekOrigin.Begin);
            return (T)binaryFormatter.Deserialize(memoryStream);
        }
    }
    #endregion

    public static int Gcd(int a, int b)
    {
        if (b == 0)
            return a;
        return Gcd(b, a % b);
    }
    public static BigInteger Gcd(BigInteger a, BigInteger b)
    {
        if (b == 0)
            return a;
        return Gcd(b, a % b);
    }

    public static BigInteger Lcm(BigInteger a, BigInteger b)
    {
        return (a * b) / Gcd(a, b);
    }

    public static BigInteger Factorial(int n)
    {
        var dp = new BigInteger[n];
        dp[0] = 1;
        for (int i = 1; i < n; i++)
        {
            dp[i] = dp[i - 1] * (i + 1);
        }
        return dp[n - 1];
    }

    public static List<long> PrimeFactorize(long n)
    {
        var bases = n;
        var num = (long)Math.Pow(n, 0.5);
        var ls = new List<long>();
        for (int i = 2; i <= num; i++)
        {
            if (n % i == 0)
            {
                n = n / i;
                ls.Add(i);
                i--;
                continue;
            }
        }
        long nnn = 1;
        foreach (var item in ls)
        {
            nnn = nnn * item;
        }
        if (nnn != bases)
            ls.Add(n);
        return ls;
    }
    public static class PrimeNumber
    {

        static long[] seedPrimes = {
        2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97
    };

        public static bool IsPrime(long num)
        {
            if (num == 1)
                return false;
            if (seedPrimes.Contains(num))
                return true;
            if (seedPrimes.Any(x => num % x == 0))
                return false;

            return (num < 2000000) ? IsPrimeBruteforce(num) : IsPrimeMillarRrabin(num);
        }

        private static bool IsPrimeBruteforce(long num)
        {
            if (num == 1)
                return false;
            if (num != 2 && num % 2 == 0)
                return false;
            if (num != 3 && num % 3 == 0)
                return false;
            if (num != 5 && num % 5 == 0)
                return false;
            long i = 0;
            while (true)
            {
                foreach (var p in seedPrimes.Skip(3).Take(8))
                {
                    var primeCandidte = p + i;
                    if (primeCandidte > Math.Sqrt(num))
                        return true;
                    if (num % (primeCandidte) == 0)
                        return false;
                }
                i += 30;
            }
        }

        private static bool IsPrimeMillarRrabin(long num)
        {
            if (num <= 1)
                return false;
            if ((num & 1) == 0)
                return num == 2;

            if (num < 100 && seedPrimes.Contains((int)num))
                return true;

            var WitnessMax = GetWitnessMax(num);

            long d = num - 1;
            long s = 0;
            while ((d & 1) == 0)
            {
                s++;
                d >>= 1;
            }
            foreach (var w in seedPrimes.Take(WitnessMax))
            {
                if (!MillarRrabin(num, s, d, w))
                    return false;
            }
            return true;
        }


        private static int GetWitnessMax(long num)
        {
            if (num < 2047)
                return 1;
            if (num < 1373653)
                return 2;
            if (num < 25326001)
                return 3;
            if (num < 3215031751)
                return 4;
            if (num < 2152302898747)
                return 5;
            if (num < 3474749660383)
                return 6;
            if (num < 341550071728321)
                return 7;
            if (num < 3825123056546413051)
                return 9;
            return 12;
        }


        private static bool MillarRrabin(long num, long s, long d, long witness)
        {
            long x = ModPow(witness, d, num);
            if (x == 1)
                return true;
            for (long r = 0; r < s; r++)
            {
                if (x == num - 1)
                    return true;
                BigInteger rem;
                BigInteger.DivRem(BigInteger.Multiply(x, x), num, out rem);
                x = (long)(rem);
            }
            return false;
        }

        private static long ModPow(long baseValue, long exponent, long modulus)
        {
            return (long)BigInteger.ModPow(baseValue, exponent, modulus);
        }

    }

    public static List<long> Make(long n)
    {
        var ls = new List<long>();
        // ls.Add(1);
        for (int i = 1; i*i <= n; i++)
        {
            if (n % i == 0)
            {
                ls.Add(i);
                if (i != 1 && i * i != n)
                {
                    ls.Add(n / i);
                }
            }
        }
        return ls;
    }
    #region 二分探索
    public static int LowerBound<T>(this IEnumerable<T> ar, int start, int end, T value, IComparer<T> comparer)
    {
        var arr = ar.ToArray();
        int low = start;
        int high = end;
        int mid;
        while (low < high)
        {
            mid = ((high - low) >> 1) + low;
            if (comparer.Compare(arr[mid], value) < 0)
                low = mid + 1;
            else
                high = mid;
        }
        return low;
    }

    public static int LowerBound<T>(this IEnumerable<T> arr, T value) where T : IComparable
    {
        return LowerBound(arr, 0, arr.Count(), value, Comparer<T>.Default);
    }

    public static int UpperBound<T>(this IEnumerable<T> ar, int start, int end, T value, IComparer<T> comparer)
    {
        var arr = ar.ToArray();
        int low = start;
        int high = end;
        int mid;
        while (low < high)
        {
            mid = ((high - low) >> 1) + low;
            if (comparer.Compare(arr[mid], value) <= 0)
                low = mid + 1;
            else
                high = mid;
        }
        return low;
    }

    public static int UpperBound<T>(this IEnumerable<T> arr, T value)
    {
        return UpperBound(arr, 0, arr.Count(), value, Comparer<T>.Default);
    }
    #endregion
    // AOJ - Power
    public static BigInteger Power(BigInteger m,BigInteger n,int p)
    {
        BigInteger amari = 1;
        while (true)
        {
            if (n / 2 >= 1)
            {
                BigInteger b = m;
                m *= m;
                if (n % 2 == 1)
                {
                    amari *= b;
                    amari %= p;
                }
                n /= 2;
            }
            m %= p;
            if (n / 2== 0)
            {
                break;
            }
        }
        return (m * amari) % p;
    }
    #endregion

}