#include <bits/stdc++.h>

using namespace std;

//判断是不是质数
bool isPrime(int n) { //最快的方法
    if (n < 2) return false;
    if (n == 2 || n == 3) return true;
    if (n % 6 != 1 && n % 6 != 5) return false;
    for (int i = 5; i <= floor(sqrt(n)); i += 6)
        if (n % i == 0 || n % (i + 2) == 0)
            return false;
    return true;
}

//转换整数到字符串
string intToStr(int n) {
    char str[256] = {0};
    sprintf(str, "%d", n);
    return str;
}

//是不是回文
bool isHuiWen(int n) {
    if (n < 10) return false;
    //将整数转为字符串
    string s = intToStr(n);
    //镜像反转
    string s1 = s;
    reverse(s1.begin(), s1.end());
    //如果源串与镜像串一致，那么是回文串
    if (s == s1) return true;
    return false;
}


int main() {
    int n;
    cin >> n;
    for (int i = 2; i < n; i++) {
        if (isHuiWen(i) && isPrime(i)) {
            cout << i << endl;
        }
    }
    return 0;
}