using System;

​

public class Program

{

    public static void Main()

    {

     int[]a=new int[5]{1,2,3,4,5};

     Console.WriteLine(IsConsecutive(a));

    }

​

    static bool  IsConsecutive (int[] a)

    {

        for (int i = 0; i < a.Length - 1; i++)

        {

            if (a[i]!=a[i+1]-1)

            {

                return false;

            }

        }

        return true;

    }

}