#include<stdio.h>
int reverse(int n);
int isprime(int n);
int main() {
	int a, b;
	scanf_s("%d %d", &a, &b);
	for (; a <= b; a++) {
		if (reverse(a)) {
			if (isprime(a))
				printf("%d\n", a);
		}
	}
}
int reverse(int n) {
	int ret = 1;
	int q = 0,p=n;
	for (; p != 0; p /= 10) {
		if (n % 10)
			q =q*10+p%10;
		else
			q *= 10;
	}
	if (q != n)
		ret = 0;
	return ret;
}
int isprime(int n) {
	int ret = 1;
	if (n != 2) {
		for (int i = 2; i * i <= n; i++) {
			if (n % i == 0)
				ret = 0;
		}
	}
	return ret;
}