Positivo y negativo Aprende programación con ejercicios C# Sharp

using System;
'Positive and negative
public class exercise15
{
    public static void Main()
    {
        int a;
        Console.Write("Enter a number: ");
        a = Convert.ToInt32(Console.ReadLine());
        if (a > 0)
            Console.WriteLine("is positive");

        if (a < 0)
            Console.WriteLine("is negative");
    }
}