#include <bits/stdc++.h>

using namespace std;
const int N = 1e8 + 10;
int primes[N], cnt;
bool st[N];

//埃拉筛
void get_primes(int n) {
    for (int i = 2; i <= n; i++) {
        if (st[i]) continue;
        primes[cnt++] = i;//都有哪些质数
        for (int j = i + i; j <= n; j += i)
            st[j] = true;
    }
}

//是不是回文数
bool isHuiWen(int n) {
    int i = n;
    int m = 0;
    while (i) {
        m = m * 10 + i % 10;
        i /= 10;
    }
    return m == n;
}

int main() {
    int a, b;
    cin >> a >> b;
    if (b > 10000000) b = 10000000;

    get_primes(b);
    //primes[]  2--->b之间所有的质数
    for (int i = 0; i < cnt; i++) {
        if (primes[i] < a)continue;
        if (isHuiWen(primes[i]))
            cout << primes[i] << endl;
    }
    return 0;
}