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

int max(int a) {
	if (a == 1)
		return 2;
	return a;
}

int zss(int a) {
	for (int i = 2; i <= pow(a, 1.0 / 2); i++) {
		if (a % i == 0) {
			return 0;
		}
	}
	return 1;
}

int jh(int a) {
	int b;
	while (1) {
		if (a == 0) {
			return b / 10;
		}
		b += a % 10;
		a /= 10;
		b *= 10;
	}
}

int main() {
	int a, b, c[100000], js = 0;
	cin >> a >> b;
	for (int i = max(a); i <= b; i++) {
		if (zss(i)) {
			int n = jh(i);
			if (zss(n)) {
				c[js] = i;
				js++;
			}
		}
	}
	if (js == 0) {
		cout << "No";
		return 0;
	}

	for (int i = 0; i < js; i++) {
		if (i == js - 1) {
			cout << c[i];
		} else {
			cout << c[i] << ",";
		}
	}
}