#include<bits/stdc++.h>
using namespace std;

int is_sushu(int n) {
	int i, mid;
	mid=(int)sqrt(n);
	for(i=2; i<=mid; i++)
		if(0 == n%i)
			return 0;
	return 1;
}
int main() {
	int n;

	printf("Enter a num: ");
	scanf("%d", &n);
	if(is_sushu(n))
		printf("%d is sushu!\n", n);
	else
		printf("%d is not sushu...\n", n);
	return 0;
}