第九次学习

using System; using System.Net.NetworkInformation;

namespace ConsoleApp1 { class Program {

    public static void RealsuShu(int n, int m)
    {
    //使用函数输出真素数

        int i, j;
        int count = 0;
        for (i = n; i <= m; i++)
        {

            for (j = 2; j <= Math.Sqrt(m); j++)
            {

                if (i % j == 0)
                {
                    break;
                }
            }

            if (j > Math.Sqrt(i))
            {
                int temp = reverseNum(i);
                if (isSuShu(temp))
                {
                    count++;
                    Console.WriteLine(i);
                }
            }
        }

        if (count == 0)
        {
            Console.WriteLine("NO");
        }
    }


    public static int reverseNum(int num)
    {
        if (num < 10)
        {
            return num;
        }

        int count = 0;
        int temp = 0;
        while (num != 0)
        {
            temp = num % 10;
            count = count * 10 + temp;
            num /= 10;
        }

        return count;
    }
    public static bool isSuShu(int num)
    { 

        for (int i = 2; i <= Math.Sqrt(num); i ++ )
        {
            if (num % i == 0)
            {
                return false;

            }
        }     
            return true;
     
    }

    public static void Main(string[] args)
    {
        int n = Convert.ToInt32(Console.ReadLine());

        int m = Convert.ToInt32(Console.ReadLine());

        RealsuShu(n, m);





    }
}

}