public class Person { private int age;

public Person(int initialAge) {
    // Add some more code to run some checks on initialAge
    if(initialAge<0){
          System.out.println("Age is not valid, setting age to 0.");
          this.age=0;   
    }
    else
    this.age=initialAge;
}

public void amIOld() {
    // Write code determining if this person's age is old and print the correct statement:
    if(age<13)
    System.out.println("You are young.");
    else if(age>=13 && age<18)
    System.out.println("You are a teenager.");
    else
    System.out.println("You are old.");

}

public void yearPasses() {
    // Increment this person's age.
    age++;
}

public static void main(String[] args) {