#include<stdio.h>
int sushu(int n);
main()
{
	int i,a,b;
	for(i=10;i<100;i++)
	{
		a=i%10;
		b=a*10+i/10;
		if(sushu(b)==1&&sushu(i)==1)
		{
			printf("%d\n",i);
		}
	}
}
int sushu(int n)
{
	int i;
	for(i=2;i<n;i++)
	{
		if(n%i==0)
		{
			return 0;
		}
	}
	if(n==1)
	{
		return 0;
	}
	else
	    return 1;
}
/**************************************************************
	Problem: 1513
	User: admin
	Language: C
	Result: Accepted
	Time:4 ms
	Memory:1036 kb
****************************************************************/