using System;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        string input = "1 2 57 A 8 9";

        if (string.IsNullOrWhiteSpace(input))

        {

            Console.WriteLine("No valid numbers provided");

            return;

        }

​

        var args = input.Split(" ");

        var valid = args.Where(a => int.TryParse(a, out _)).Select(a => int.Parse(a)).OrderByDescending(a => a).ToList();

        if (valid.Count == 0)

        {

            Console.WriteLine("No valid numbers provided");

            return;

        }

​

        Console.WriteLine($"You provided {valid.Count} valid numbers with {valid.First()} being the highest");

    }

} 

​