#include <iostream>
#include <cmath>
#include <string>
using namespace std;
bool zhishu(int n)
{
	for (int i = 2; i <= sqrt(n); i++)
	{
		if (n % i == 0)return false;
	}
	return true;
}

int main()
{
	int a, b;
	cin >> a >> b;
		for (int i = a; i <= b; i++)//判断回文数 101 1001 12021 0 length-1 1 length-2
		{
			if (i == 2 || i % 2 != 0)
			{
				if (i < 10&& zhishu(i))
				{
					cout << i << endl;
					continue;
				}
				if(i==11)
				{
					cout << 11 << endl;
					continue;
				}
				if (i>11&&i % 11 != 0&&to_string(i).length()%2!=0)
				{
					bool flag = true;
					for (int j = 0; j <= (to_string(i).length() / 2) - 1; j++)
					{
						if (to_string(i)[j] != to_string(i)[to_string(i).length() - j - 1])flag = false;
					}
					if (flag == true && zhishu(i))cout << i << endl;
				}
			}
		}
	
}

新手求助，后3个TLE