using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Random ran=new Random((int)DateTime.Now.Ticks);

        Dictionary<int,int> dict=new Dictionary<int,int>();

        while(dict.Count<10){

            int index = ran.Next(1,21);

            int price = ran.Next(1,10001);

            if(!dict.ContainsKey(index))

            dict.Add(index,price);

        }

        List<int> list=new List<int>();

        Dictionary<int,int>.ValueCollection values= dict.Values;

        foreach(int value in values)  {

            list.Add(value);    

        }

        list.Sort();

        int length =list.Count;

        int max = 0;    

        foreach (var item in dict)

        {

            if(item.Value==list[length-1])

                max = item.Key;         

        }

        List<int> list2=new List<int>();

        for(int i=1;i<=20;i++){

            if(!dict.ContainsKey(i))

                list2.Add(i);       

        }

        Console.WriteLine("Please input a number between 1 to 20");

        int guess = int.Parse(Console.ReadLine());

        /*int result =-1;

            dict.TryGetValue(guess,out result);

            if(result==0)

            */

            if(!dict.ContainsKey(guess))

                Console.WriteLine("BANG,You could have won the most money if you guess {0}",max);

        else{

                Console.WriteLine("You win {0} dollars,you could have failed if you guess the following numbers",list[guess]);

                foreach(int a in list2)

                Console.Write(a+" ");

            }

        }   

    }

​