#include <bits/stdc++.h>
using namespace std;

bool sushu(int n){
	if(n <= 1) return false;
	for(int i = 2;i <= sqrt(n);i++){
		if(n % i == 0){
			return false;
		}
	}
	
	return true;
}


int main(){
	for(int i = 10;i <= 99;i++){
		int j = i % 10 * 10 + i / 10;
		if(sushu(i) && sushu(j)){
			cout<<i<<endl;
		}
	} 
}


/**************************************************************
	Problem: 1513
	User: admin
	Language: C++
	Result: Accepted
	Time:4 ms
	Memory:2072 kb
****************************************************************/