#include <iostream>
#include <string>
#include <algorithm>
#include <cmath>
using namespace std;

bool isprime(long long n);
bool ispalindrome(long long n);

int main() {
    long long a, b;
    cin>>a>>b;
    for (int i=a;i<=b;i++){
        if (ispalindrome(i) && isprime(i)){
            cout<<i<<endl;
        }
    }

    return 0;
}

bool isprime(long long n) {
    if (n <= 1) {
        return false;
    }
    long long k = sqrt(n);
    for (long long i = 2; i <= k; i++) {
        if (n % i == 0) {
            return false;
        }
    }
    return true;
}

bool ispalindrome(long long n){
    string num = to_string(n);
    string reverse_num = num;
    reverse(reverse_num.begin(), reverse_num.end());
    if (num == reverse_num) {
        return true;
    }
    return false;
}