public static int NhapN(){
int n = int.Parse(Console.ReadLine());
public static int[] NhapMang(int n) {
for (int i = 0; i < n; i++) {
arr[i] = int.Parse(Console.ReadLine());
public static int KiemTra(int[] arr, int n) {
for (int i = 0; i < n; i++) {
for (int j = 0; j < arr[i]/2; j++) {
public static void Main()
int result = KiemTra(arr, n);