+ L R' adds a segment from point L to point R. You program should print the number of segments that are (non-strictly) inside the new one.
- L R' removes one segment from point L to point R. If there is no such segment, ignore this query.
- L R' or '
+ L R', where L and R are integers (-109 ≤ L < R ≤ 109). There will be no more than 250 · 103 queries.
+ L R' query, containing the number of segments inside the added segment.
+ 1 2 + 1 2 + 0 3 - 1 2 + 1 2
0 1 2 1