#include "stdio.h"
#include "conio.h"
int kiemtrasnt(int n)
{
	for (int i = sqrt(float(n)); i >= 2; i--)
		if (n % i == 0) return 0;
	if(n > 1) return 1;
	else return 0;
}
void xoa(int a[], int k, int &n)
{
	for (int i = k; i < n - 1; i++)
	{
		a[i] = a[i + 1];
	}
	n--;
}
void xoant(int a[], int &n)
{

	for (int i = 0; i < n; i++)
		if (kiemtrasnt(a[i]) == 1) xoa(a, i, n);
}
int timk(int a[], int k, int n)
{
	int dem = 0;
	for (int i = 0; i < n; i++)
	if (a[i] == k) dem++;
	return dem;
}
int main(void)
{
	int n, b, k, m;
	printf("Nhap n: ");
	scanf_s("%d.\n", &n);
	int *a = new int[n];
	for (int i = 0; i < n; i++)
	{
		printf("nhap phan tu thu %d: ", i + 1);
		scanf("%d.\n", &a[i]);
	}
	for (int i = 0; i < n; i++)
		printf("%d\t", a[i]);
	printf("\n1.Xoa so nguyen to\n2.Liet ke so phan tu bang k\nLua chon: ");
	scanf("%d.\n", &b);
	switch (b)
	{
	case 1:
		xoant(a, n);
		for (int i = 0; i < n; i++)
			printf("%d\t", a[i]);
		break;
	case 2:
		printf("\nNhap k: ");
		scanf("%d.\n", &k);
		m = timk(a, k, n);
		printf("So phan tu bang k: %d\n", m);
		if (m % 3 != 0) printf("khong ");
		printf("chia het\n");
		break;
	default:
		break;
	}
}