static class Time implements Comparable<Time> {

int start, end;

Time(int start, int end) {

this.start = start;

this.end = end;

}

@Override

public int compareTo(Time time) {

if(this.start != time.start) {

return this.start - time.start;

}

return this.end - time.end;

}

}

public int solution(String[][] book_time) {

List<Time> list = new ArrayList<>();

for(int i = 0; i < book_time.length; i++) {

int start = Integer.parseInt(book_time[i][0].substring(0, 2)) * 60 + Integer.parseInt(book_time[i][0].substring(3, 5));

int end = Integer.parseInt(book_time[i][1].substring(0, 2)) * 60 + Integer.parseInt(book_time[i][1].substring(3, 5));

list.add(new Time(start, end));

}

Collections.sort(list);

PriorityQueue<Integer> pq = new PriorityQueue<>();

pq.offer(list.get(0).end + 10);

for(int i = 1; i < list.size(); i++) {

if(pq.peek() <= list.get(i).start) {

pq.poll();

}

pq.offer(list.get(i).end + 10);

}

return pq.size();

}

}