using System;

using System.Collections.Generic;   

public class Program

{

    public static void Main()

    {

        int[] n ={1,12,3,4,75,6,7,8,9};

        List<int>r = new List<int>(n);

        r.Add(25);

        r.Add(32);

        Console.WriteLine(r.IndexOf(75));

    }

}