#include<iostream>
#include<cmath>
using namespace std;
bool hw(int n);
bool zs(int b){
int y=sqrt(b);
for(unsigned long i=2;i*i<=b;i++){
if(b%i==0){
return 0;
}
}
return 1;
}
bool hw(int a){
	unsigned long n=a,e=0;
	while(n!=0){
		e=e*10+n%10;
		n/=10;
	}
	if(e==a)return 1;
	return 0;
}
int main()
{	
	unsigned long a,b;
	cin>>a>>b;
	for(unsigned long i=a;i<=b;i++)
	{
		if(hw(i)&&zs(i))
		cout<<i<<endl;
	}
	return 0;
}