using System;

class BinarySearch
{
    static void Main()
    {
        Console.Write("Enter Array Lenght:");
        int n = int.Parse(Console.ReadLine());
        Console.Write("Member to search:");
        int m = int.Parse(Console.ReadLine());
        Console.WriteLine("Input array elements:");
        int[] array = new int[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = int.Parse(Console.ReadLine());
        }
        Array.Sort(array);
        Console.Write("Index of searching member: ");
        Console.Write(Array.BinarySearch(array, m));
        Console.WriteLine();
    }
}