using System;

using System.Linq;

​

public class Program

{

    public static int solution(int[] A)

    { 

            long minDiff = long.MaxValue; //set max possible value!

            long rightSum = A.Sum(); //Total the array contents

            long leftSum = 0L;

            for (var i = 0; i < A.Length - 1; i++)

            {

                leftSum += A[i]; //add to left (0)

                rightSum -= A[i]; //subtract from right (total)

                long currentDiff = Math.Abs(rightSum - leftSum); //subtract, ensuring a positive number at all times

​

                if (minDiff > currentDiff) 

                    minDiff = currentDiff; //update with the smallest number

            }

            return (int)minDiff;

    }

​

    public static void Main()

    {

        Console.WriteLine(solution(new int[]

        {

        3, 1, 4, 7

        }

​

        ));

    }

}