Random number generator, C#

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using System;
using System.Collections.Generic;
using System.Linq;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            bool tryagain=true;
  int big;
  int small;
      Random r=new Random();
    Console.WriteLine("Hello,this is a random number generator made by Matthew");
    Console.WriteLine("\nWhat is the smallest number?\n");
    int number1=Convert.ToInt32(Console.ReadLine());
    Console.WriteLine("\nOk,what is the biggest number?\n");
int number2=Convert.ToInt32(Console.ReadLine());
if(number1>number2){big=number1;
small=number2;}
else{small=number1;
    big=number2;
}
Console.WriteLine("");
while(tryagain){
    for(int a=0;a<3;a++){
    Console.Write(".");
    System.Threading.Thread.Sleep(500);}
    Console.WriteLine("\n\nYour random number is "+r.Next(small,big+1));
      Console.WriteLine("\nDo you want to generate it again?\n");
      string b=Console.ReadLine();
      if(b.ToLower()!="yes"){Console.WriteLine("\nThank you for trying my random number generator!");
          tryagain=false;
      }else{Console.Write("\n");}
  }}
  }

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