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 TimAmDauTien(int[] arr) {
for (int i = 0; i < n; i++) {
public static void Main()
int result = TimAmDauTien(arr);