Я понимаю ,что вопрос смешной но нужна помощь =)))

public class Solution {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader (new InputStreamReader(System.in));
        String fileName = reader.readLine();

        FileInputStream stream = new FileInputStream("src/com/javarush/task/task18/task1801/exemple.txt");
        List <Integer> result = new ArrayList<>();
        while (stream.available() > 0) {
            int data = stream.read();
            result.add(data);
        }
        stream.close();
        Collections.sort(result);
        System.out.println(result.get(0));
    }
}

public class Solution {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String fileName = reader.readLine();

        FileInputStream stream = new FileInputStream(fileName); // тут был путь "/home/masha/txt.txt"
        List<Integer> result = new ArrayList<>();
        while (stream.available() > 0) {
            int data = stream.read();
            result.add(data);
        }
        stream.close();
        Collections.sort(result);
        System.out.println(result.get(result.size() - 1));
    }
}