Не проходит проверку

package com.javarush.task.task19.task1907;

/*
Считаем слово
*/

import java.io.*;

public class Solution {
    public static void main(String[] args) throws IOException {

        BufferedReader rd = new BufferedReader(new InputStreamReader(System.in));
        String name = rd.readLine();
        rd.close();

        FileReader fr = new FileReader(name);
        ByteArrayOutputStream sb = new ByteArrayOutputStream();


        while (fr.ready()) {
            sb.write(fr.read());
        }

        String sub = (" " + sb.toString()+" ").replace(" ", "  ");
        String rep = sub.replace(" world ", "");
        System.out.println((sub.length()-rep.length())/7);

        fr.close();

    }
}