using System;

public class Program

{

    public static void Main()

    {

            Console.OutputEncoding = System.Text.Encoding.UTF8;

            Console.WriteLine("nhap ho va ten");

            string s = Console.ReadLine();

            string ho, tenlot, ten;

            bool xet = s.Any(char.IsDigit);

           while(xet==true)

            {

                Console.WriteLine("nhap lai");

                s = Console.ReadLine();

                xet = s.Any(char.IsDigit);

            }

            string[] tach = s.Split(" ");

            ho = tach[0];

            Console.ReadLine(ho);

​

    }

}