#include <bits/stdc++.h>
using namespace std;

int prime(int n) {
	if (n == 1)
		return 0;
	for (int i = 2; i * i <= n; i++) {
		if (n % i == 0)
			return 0;
	}
	return 1;
}
int ctf(int n) {
	int temp = 0;
	while (n) {
		temp = temp * 10 + n % 10;
		n /= 10;
	}
	return temp;
}
int main() {
	int m, n, t = 0, a[100000] = {0}, temp;
	cin >> m >> n;
	for (int i = m; i <= n; i++) {
		if (prime(i))
			a[t++] = i;
	}
	int sign = 0;
	for (int i = 0; i < t; i++) {
		int s = a[i];
		temp = 0;
		temp = ctf(s);
		if (prime(temp) && i != t - 1) {
			cout << a[i] << ',';
			sign = 1;
		}
		if (prime(temp) && i == t - 1) {
			cout << a[i];
			sign = 1;
		}
	}
	if (sign == 0)
		cout << "No";
	return 0;
}