Activity Tracker

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner;
import java.util.SortedMap;
import java.util.TreeMap;

public class ActivityTracker {

    public static void main(String[] args) {

        Comparator<Entry<String, Integer>> cValue = new Comparator<Entry<String, Integer>>() {

            @Override
            public int compare(Entry<String, Integer> o1, Entry<String, Integer> o2) {
                return o2.getValue().compareTo(o1.getValue());
            }
        };

        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        SortedMap<Integer, TreeMap<String, Integer>> activity = new TreeMap<>();

        for (int i = 0; i < n; i++) {
            String date = sc.next("[0-9]{2}/[0-9]{2}/[0-9]{4}");
            int month = Integer.parseInt(date.substring(3, 5));
            String name = sc.next();
            int distance = sc.nextInt();

            if (!(activity.containsKey(month))) {
                activity.put(month, new TreeMap<String, Integer>());
            }
            TreeMap<String, Integer> dist = activity.get(month);
            int d = 0;
            if (dist.containsKey(name)) {
                d = dist.get(name);
            }
            dist.put(name, d + distance);
        }
        sc.close();

        for (Integer month : activity.keySet()) {
            List<Map.Entry<String, Integer>> l = new ArrayList<Map.Entry<String, Integer>>(activity.get(month).entrySet());
            Collections.sort(l, cValue);
            System.out.print(month + ": ");

            boolean first = true;
            for (Entry<String, Integer> entry : l) {
                if (!first) {
                    System.out.print(", ");
                }
                first = false;
                System.out.print(entry.getKey() + "(" + entry.getValue() + ")");
            }
            System.out.println();
        }
    }
}