Untitled

using System;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            DoFizzBuzz();
        }
        
        private static void DoFizzBuzz()
        {
            for (int i = 1; i <= 20; i++)
            {
                var fizz = i % 3 == 0;
                var buzz = i % 5 == 0;
                if (fizz && buzz)
                    Console.WriteLine ("FizzBuzz");
                else if (fizz)
                    Console.WriteLine ("Fizz");
                else if (buzz)
                    Console.WriteLine ("Buzz");
                else
                    Console.WriteLine (i);
            }
        }
    }
}