#include<iostream>
#include<cstdio>
using namespace std;
bool jc(long long x)
{
	long long y=x,num=0;
	while (y!=0)
	{
		num=num*10+y%10;
		y/=10;
	}
	if(num==x)return 1;
	else return 0;
}
int main()
{
	bool flag=0; 
	long long a,b;
	cin>>a>>b;
    if(a%2==0)
    a++;
 	for(long long i=a;i<=b;i+=2)
	{
		flag=0;
		if(jc(i)==1)
		{
		for(int j=3;j*j<=i;j+=2)
		{
			if(i%j==0)
			{
			
				flag=1;
					
				break;
			}
		}
		if(flag==0)
		{
		cout<<i<<endl;	
	    }	
		} 	
	}
	return 0;
}

开o2AC，否则tle 所以o2是啥