#include<iostream>
using namespace std;

bool pd_h(long long x);
bool prime(long long x);

int main()
{
	long long a,b;
	cin>>a>>b;
	for(int i=a;i<=b;i++)
	{
		if(pd_h(i)==1&&prime(i)==1)
		cout<<i<<endl;
	}
	return 0;
}

bool pd_h(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;
}
bool prime(long long x)
{
    if(x==1)return false;
    if(x==2||x==3)return true;
    if(x%6!=1&&x%6!=5)return false;
    for(int i=5;i*i<=x;i+=6)
    {
        if(x%i==0||x%(i+2)==0)return false;
    }
    return true;
}