#include <iostream>
#include <vector>
#include <cmath>
using namespace std;

bool isPalindrome(int x) {
    if (x < 0) {
        return false;
    }
    int temp = x;
    int reversed = 0;
    while (temp > 0) {
        reversed = reversed * 10 + temp % 10;
        temp /= 10;
    }
    return reversed == x;
}

bool isPrime(int num) {
    if (num <= 1) {
        return false;
    }
    if (num == 2) {
        return true;
    }
    if (num % 2 == 0) {
        return false;
    }
    for (int i = 3; i <= sqrt(num); i += 2) {
        if (num % i == 0) {
            return false;
        }
    }
    return true;
}

int main() {
    int a, b;
    cin >> a >> b;
    for (int i = max(a, 2); i <= b; i++) {
        if (isPalindrome(i) && isPrime(i)) {
            cout << i << endl;
        }
    }
    return 0;
}