include<bits/stdc++.h>

using namespace std; long long x, y, a, b, c, d, e;

int main() {

cin >> x >> y;

for (long long i = x; i <= y; i++) {
    long long  t = i;
    long long  w = 0;
    while (t > 0) {
        w = w * 10 + t % 10;
        t = t / 10;
    }
    if (w != i){
    	continue;
	}
    long long z = 1;
    if (i < 2) {
    z = 1;	
	}
    for (long long k = 2; k * k <= i; k++) {
        if (i % k == 0) {
            z =0;
            break;
        }
    }
    
    if (z){
    	cout << i << endl;
	} 
}

return 0;

}