#include<bits/stdc++.h>

using namespace std;

int xs(int x)
{
	long long y = 0,z = x;
	while(z > 0)
	{
		y = (z % 10) + y * 10 ;
		z /= 10;
	}
	if(y == x) return 1;
	else return 0;
}

bool iPme(int x)
{
	if(x == 0 || x == 1 || x == 4) return 0;
	for(int i = 2;i * i <= x;i++)
	{
		if(x % i == 0)return 0;
	}
	return 1;
}

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