using System;

public class Program

{

    public static void Main()

    {

        int limit = 18;

        int age = 0;

        //label

        start:

            Console.WriteLine("Type your age");

            age = Convert.ToInt32(Console.ReadLine());

            //If the age is less than limit (18) age < limit = true

        if (age < limit){

        goto start;

        }

​

        //Show the age

        Console.WriteLine("The age {0} is valid!",age);

    }

}