#include<stdio.h>
int main()
{
int A,y,n;
scanf("%d",&A);
for(n=2;n<=A-1;n++)
y=A%n;
scanf("%d",&y);
if(y==0&&y!=0)
printf("%d yes",A);
else
printf("%d no",A);
}
#include<stdio.h>
int main()
{
int A,y,n;
scanf("%d",&A);
for(n=2;n<=A-1;n++)
y=A%n;
scanf("%d",&y);
if(y==0&&y!=0)
printf("%d yes",A);
else
printf("%d no",A);
}