#include<studio.h>
int main()
{
int n,i;
printf("please enter a integer number,n=?");
scanf("%d",&n);
for(i=2;i<n;i++)
if(n%i==0)break;
if(i<n)printf("%d is not a prime number.\n");
else printf("%d is a prime number.\n");
return 0;
}