Почему валидатор не принимает?

while (matcher.find()) {
                System.out.println(matcher.group());
                count++;
}

"(^|\\p{P}|\\s)world($|\\p{P}|\\s)"

package com.javarush.task.task19.task1907;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/*
Считаем слово
*/

public class Solution {
    public static void main(String[] args) throws IOException {
        List<Character> list = new ArrayList<>();
        BufferedReader name = new BufferedReader(new InputStreamReader(System.in));
        FileReader input = new FileReader(name.readLine());
        BufferedReader reader = new BufferedReader(input);
        Pattern pattern = Pattern.compile("(?<=^| |\\p{P})world(?= |$|\\p{P})");
        Matcher matcher;
        int count = 0;
        while (reader.ready()) {
            String str = reader.readLine();
            matcher = pattern.matcher(str);
            while (matcher.find())
                count++;

        }
        System.out.println(count);
        reader.close();
        name.close();
    }
}

"(^|\\p{P}|\\s)world(?=($|\\p{P}|\\s))"