using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {

            Console.WriteLine("moi ban nhap so : ");
            string so = Console.ReadLine();
            int so2;
            if (int.TryParse(so, out so2) == false) ;
            {
                Console.WriteLine("du lieu nhap sai");
                //return; 
            }
            else
            {
                Console.WriteLine("du lieu nhap dung");
            }
             

                
        
        Console.ReadKey();
            
        }
    }
}
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