HackerRank Java- Inheritance I

The code above is provided for you in your editor. You must add a sing method to the Bird class, then modify the main method accordingly so that the code prints the following lines:

I am walking
I am flying
I am singing

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

class Animal{
	void walk(){
		System.out.println("I am walking");
	}
}

class Bird extends Animal {
    void fly() {
        System.out.println("I am flying");
    }
    void sing() {
        System.out.println("I am singing");
    }
}
public class Solution{

   public static void main(String args[]){

	  Bird bird = new Bird();
	  bird.walk();
	  bird.fly();
      bird.sing();
	
   }
}