#include<bits/stdc++.h>
using namespace std;
const int N=1e9+10;
long long cnt=0,p[N/10],zs[N/10];
void shsu(int n)
{
	for(int i=2;i<=n;i++){
		if(p[i]==0)zs[++cnt]=i;
		for(int j=1;j<=cnt;j++){
			long long m=zs[j]*i;
			if(m>n)break;
			p[m]=1;
			if(i%zs[j]==0)break;
		}
	}
}
bool ishw(long long a)
{
	long long s=0,n,y=a;
	while(a>0){
		n=a%10;
		s=s*10+n;
		a=a/10;
	}
	if(s==y)return 1;
	else return 0;
}
int main()
{
	long long a,b;
	cin>>a>>b;
	shsu(b+100);
	for(int i=1;i<=cnt;i++){
		if(zs[i]<a)continue;
		if(zs[i]>b)break;
		if(ishw(zs[i]))cout<<zs[i]<<endl;
	}
	return 0;
}