Population Counter

package exercise;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.stream.Collectors;

public class Population {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        Map<String, Map<String, Long>> data = new LinkedHashMap<>();

        String line;
        while (!"report".equals((line = reader.readLine()))) {
            String[] tokens = line.split("\\|");
            String city = tokens[0];
            String country = tokens[1];
            Long population = Long.parseLong(tokens[2]);

            if (!data.containsKey(country)) {
                data.put(country, new LinkedHashMap<>());
            }
            data.get(country).put(city, population);
        }

        data.entrySet().stream().sorted((c1, c2) -> Long.compare(c2.getValue().values().stream().collect(Collectors.summarizingLong(Long::valueOf)).getSum()
                , c1.getValue().values().stream().collect(Collectors.summarizingLong(Long::valueOf)).getSum())).forEach(country -> {
            System.out.println(String.format("%s (total population: %d)", country.getKey(),
                    country.getValue().values().stream().collect(Collectors.summarizingLong(Long::valueOf)).getSum()));
            country.getValue().entrySet().stream().sorted((p1, p2) -> p2.getValue().compareTo(p1.getValue()))
                    .forEach(pair -> System.out.println(String.format("=>%s: %d", pair.getKey(), pair.getValue())));
        });
    }
}