Matching Specific String

Task

You have a test string S. Your task is to match the string hackerrank. This is case sensitive.

Note

This is a regex only challenge. You are not required to write code.
You only have to fill in the regex pattern in the blank (_________).

import java.io.*;

import java.util.*;

import java.text.*;

import java.math.*;

import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {

        Regex_Test tester = new Regex_Test();

        tester.checker("hackerrank");

    }
}

class Regex_Test {

    public void checker(String Regex_Pattern){

        Scanner Input = new Scanner(System.in);

        String Test_String = Input.nextLine();

        Pattern p = Pattern.compile(Regex_Pattern);

        Matcher m = p.matcher(Test_String);

        int Count = 0;

        while(m.find()){

            Count += 1;

        }

        System.out.format("Number of matches : %d",Count);

    }

}