#include <stdio.h>
#include <math.h>

int is_prime(int x) {
	int i;
    if (x <= 1) {
        return 0;
    }
    for (i = 2; i <= sqrt(x); ++i) {
        if (x % i == 0) {
            return 0;
        }
    }
    return 1;
}

int absolute(int x) {
    int reverse = 0, original = x;
    while (x > 0) {
        int digit = x % 10;
        reverse = reverse * 10 + digit;
        x /= 10;
    }
    return is_prime(original) && is_prime(reverse);
}

int main() {
    int a, b,i;
    scanf("%d %d", &a, &b);

    for (i = a; i <= b; ++i) {
        if (absolute(i)) {
            printf("%d\n", i);
        }
    }

    return 0;
}