#include<bits/stdc++.h>
using namespace std;
bool  ss(int n){
	bool  r=true;
	if(n<2) r=false;
	else{
		for(int i=2;i<=sqrt(n);i++){
			if(n%i==0){
				r=false;
				break;	
				
			}
	
	}
		
	}
	 return r;
}
    int  main(){
    	int g,s;
    	for(int i=10;i<=99;i++){
    		g=i%10;
    		s=i/10%10;
    		if(ss(i)&&ss(g*10+s)){
    			cout<<i<<endl;	
    		    	
    		}
    	} 
    	return 0;
    }
/**************************************************************
	Problem: 1513
	User: chenyaohuo
	Language: C++
	Result: Accepted
	Time:4 ms
	Memory:2072 kb
****************************************************************/