import java.io.File;
import java.lang.Integer;
import java.lang.System;
import java.lang.reflect.Array;
import java.security.MessageDigest;
import java.util.Comparator;
import java.security.NoSuchAlgorithmException;
import java.util.*;
import java.io.BufferedReader;
import java.io.FileReader;
import java.util.InputMismatchException;

public class MP1 {
    Random generator;
    String userName;
    String inputFileName;

    static final String delimiters = " \t,;.?!-:@[](){}_*/";
    static final String[] stopWordsArray = {"i", "me", "my", "myself", "we", "our", "ours", "ourselves", "you", "your", "yours",
            "yourself", "yourselves", "he", "him", "his", "himself", "she", "her", "hers", "herself", "it", "its",
            "itself", "they", "them", "their", "theirs", "themselves", "what", "which", "who", "whom", "this", "that",
            "these", "those", "am", "is", "are", "was", "were", "be", "been", "being", "have", "has", "had", "having",
            "do", "does", "did", "doing", "a", "an", "the", "and", "but", "if", "or", "because", "as", "until", "while",
            "of", "at", "by", "for", "with", "about", "against", "between", "into", "through", "during", "before",
            "after", "above", "below", "to", "from", "up", "down", "in", "out", "on", "off", "over", "under", "again",
            "further", "then", "once", "here", "there", "when", "where", "why", "how", "all", "any", "both", "each",
            "few", "more", "most", "other", "some", "such", "no", "nor", "not", "only", "own", "same", "so", "than",
            "too", "very", "s", "t", "can", "will", "just", "don", "should", "now"};

    static final Set<String> stopWordsSet = new HashSet<String>(Arrays.asList(stopWordsArray));

    void initialRandomGenerator(String seed) throws NoSuchAlgorithmException {
        MessageDigest messageDigest = MessageDigest.getInstance("SHA");
        messageDigest.update(seed.toLowerCase().trim().getBytes());
        byte[] seedMD5 = messageDigest.digest();

        long longSeed = 0;
        for (int i = 0; i < seedMD5.length; i++) {
            longSeed += ((long) seedMD5[i] & 0xffL) << (8 * i);
        }

        this.generator = new Random(longSeed);
    }

    // not using this till now
    Integer[] getIndexes() throws NoSuchAlgorithmException {
        Integer n = 10000;
        Integer number_of_lines = 50000;
        Integer[] ret = new Integer[n];
        this.initialRandomGenerator(this.userName);
        for (int i = 0; i < n; i++) {
            ret[i] = generator.nextInt(number_of_lines);
        }
        return ret;
    }

    public MP1(String userName, String inputFileName) {
        this.userName = userName;
        this.inputFileName = inputFileName;
    }

    public String[] process() throws Exception {
        String[] ret = new String[20];
        HashMap<String, Integer> counter = new HashMap<String, Integer>();

        // get the indices for the user id
        Integer[] indices = this.getIndexes();
        Arrays.sort(indices);

        // reading the file here
        List<String> lines = new ArrayList<String>();
        BufferedReader br = new BufferedReader(new FileReader(inputFileName));
        String line = br.readLine();
        while (line != null) {
            lines.add(line);
            line = br.readLine();
        }

        String[] validLines = new String[indices.length];
        for (int i=0; i < validLines.length; i++) {
            validLines[i] = lines.get(indices[i]);
        }


        for (String topic: validLines) {
            ArrayList<String> words = splitWords(topic);
            for (String word: words) {
                int count = counter.containsKey(word) ? counter.get(word) + 1 : 1;
                counter.put(word, count);
            }
        }

        // build a sorted map
        // NOTE: Extremely shitty hack to get the first 20
        TreeMap<String, Integer> sortedMap = SortByValue(counter);
        int index = 0;
        for (Map.Entry<String, Integer> entry : sortedMap.entrySet()) {
            if (index < 20) {
                ret[index] = entry.getKey();
                index += 1;
            } else {
                break;
            }
        }

        return ret;
    }

    private TreeMap<String, Integer> SortByValue(HashMap<String, Integer> map) {
        ValueComparator vc = new ValueComparator(map);
        TreeMap<String, Integer> sortedMap = new TreeMap<String, Integer>(vc);
        sortedMap.putAll(map);
        return sortedMap;
    }

    public ArrayList<String> splitWords(String title) {
        StringTokenizer st = new StringTokenizer(title, delimiters);
        ArrayList<String> words = new ArrayList<String>();
        while (st.hasMoreTokens()) {
            String token = st.nextToken().trim().toLowerCase();
            if (!stopWordsSet.contains(token)) {
                words.add(token);
            }
        }
        return words;
    }

    public static void main(String[] args) throws Exception{
        if (args.length < 1){
            System.out.println("MP1 <User ID>");
        }
        else {
            String userName = args[0];
            String inputFileName = "./input.txt";
            MP1 mp = new MP1(userName, inputFileName);
            String[] topItems = mp.process();
            for (String item: topItems){
                System.out.println(item);
            }
        }
    }
}

class ValueComparator implements Comparator<String> {
    Map<String, Integer> map;

    public ValueComparator(Map<String, Integer> base) {
        this.map = base;
    }

    public int compare(String a, String b) {
        if (map.get(a) > map.get(b)) {
            return -1;
        } else if (map.get(a) < map.get(b)) {
            return 1;
        } else { // handle case of inequality
            return a.compareTo(b);
        }
    }
}