#include<stdio.h>

int main(){
	int n, i, c = 0;
	printf("nhap n: ");
	scanf("%d", &n);
    for(i = n;i > 0;i--){
    	if(n % i == 0){
    		c += 1;
		}
	}
	if(c == 2){
		printf("So nguyen to!");
	} else{
		printf("Khong phai so nguyen to!");
	}
    
    return 0;

}