using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        List<int> nums = new List<int>(){1,2,3,6,7,8};

        int count = nums.Count;

        for(int i=0;i<count;i++){

            if((nums[i+1]-nums[i])>1){

                Console.WriteLine("Missed Elememt is :" [i]);

            }

        }

    }

}