using System;

public class Program

{

    // find first element that greater than given target

    static int next(int[] arr, double target)

    {

        int start = 0, end = arr.Length - 1;

        int ans = -1;

        while (start <= end)

        {

            int mid = (start + end) / 2;

            // Move to right side if target is

            // greater.

            if (arr[mid] <= target)

            {

                start = mid + 1;

            }

             // Move left side.

            else

            {

                ans = mid;

                end = mid - 1;

            }

        }

        return ans;

    }

    static double avg_first_last(int[] arr)

    {

        return (arr[0]+arr[arr.Length - 1])/2;

     }

    static bool isMajority(int index, int n)

    {       

        return index < n/2;

    }

    public static void Main()

    {

        int[] arr = { 1, 2, 3, 9, 10, 12 ,13 ,14 };

        int n = arr.Length;

        Console.WriteLine(avg_first_last(arr));

        Console.WriteLine(next(arr, 7));

//      Console.WriteLine(isMajority(next(arr, 5),n));

        Console.WriteLine(isMajority(next(arr, avg_first_last(arr)),n));

    }

}