#include <stdio.h>
int func(int num);void main ()
{
int num, i;
scanf ("%d", &num);
for (i=1; i<num; i++)
{
if (func(num)<=func(i))
{
printf ("no");
i=num+1;
}
if (i==num)
printf ("yes");
}
int func(int num)
{
int count=0, i;
for (i=2; i<num; i++)
if (num%i==0)
count++;
return count;
}