5. Login

import java.util.Scanner;

public class Ex5 {
    public static void main(String[] args) {
        Scanner sacnner = new Scanner(System.in);

        String username = sacnner.nextLine();
        String password = "";
        String passwordTry = "";
        int counter1 = 0;

        for (int counter = username.length() - 1; counter >= 0;counter--){
            password += username.charAt(counter);
        }

        while (!(passwordTry.equals(password)) && counter1 < 4){
            passwordTry = sacnner.nextLine();
            counter1++;
            if (passwordTry.equals(password)){
                System.out.printf("User %s logged in.",username);
                return;
            }
            if (counter1 <= 3) {
                System.out.println("Incorrect password. Try again.");
            }
        }
        System.out.printf("User %s blocked!",username);
    }
}