include <stdio.h>

int main() {

          int n, i, ngt=1;

          do {

                   printf("Nhap n: ");

                   scanf("%d", &n);

          } while(n<=0);

          for(i=2; i<=sqrt(n); i++) {

                   if(n%i==0)

                             ngt = 0;

          }

          if(ngt==0)

                   printf("\nSo %d khong phai la so nguyen to", n);

          else

                   printf("\nSo %d la so nguyen to", n