#include<stdio.h>
int con(int x) {
	int a = 0;
	int y = x;
	while (y != 0) {
		a = a * 10 + y%10;
		y /= 10;
	}if (a == x) {
		return 1;
	}
	else return 0;
}
int main() {
	int a,b,c=0;
	scanf("%d %d", &a,&b);
	for (int i = a; i <= b; i++) {
		for (int k = 2; k < i; k++) {
			c = i % k;
			if (c == 0) break;
		}if (c != 0 && con(i) == 1) {
			printf("%d\n", i);
		}
	}
	return 0;
	}