public static void Main()
var counterThread = new Thread(countThread);
var counterdownThread = new Thread(countdownThread);
counterdownThread.Start();
static void countThread(){
for (int i = 1; i< 5; i++){
Console.WriteLine($"Counter thread {Thread.CurrentThread.ManagedThreadId} i :{i}");
static void countdownThread(){
for (int i = 5; i>0; i--){
Console.WriteLine($"Countdown thread {Thread.CurrentThread.ManagedThreadId} i :{i}");