# include <stdio.h>
bool IsPrime(int val)
{
int i;
for (i=2; i<val; ++i)
{
if (val%i == 0)
break;
}
if (i == val)
return true;
else
return false;
}
int main(void)
{
int m;
scanf("%d", &m);
if ( IsPrime(m) )
printf("Yes!\n");
else
printf("No!\n");
return 0;
}