#include<bits/stdc++.h>
using namespace std;
bool a[17400001]={1,1};
long long n,m,cnt,b[17400001];
int main()
{
	cin>>m>>n;
	for(int i=2;i<=n;i++)
	{
		if(a[i]==0)
			b[++cnt]=i;
		for(int j=1;j<=cnt;j++)
		{
			if(i*b[j]>n)
				break;
			a[i*b[j]]=1;
			if(i%b[j]==0)
				break;
		}
	}
	for(int i=1;i<=cnt;i++)
	{
		if(b[i]<m)
			continue;
		else
		{
			int e[11],z=0,x=0,p=b[i];
			while(p>0)
			{
				e[z]=p%10;
				p/=10;
				z++;
			}
			if(z>2&&z%2==0)
				continue;
			for(int l=0,j=z-1; l<=j; l++,j--)
				if(e[l]!=e[j])
					x=1;
			if(x==0)
				cout<<b[i]<<endl;
		}
	}
	return 0;
}