D. Vasiliy's Multisettime limit per test4 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputAuthor has gone out of the stories about Vasiliy, so here is just a formal task description.You are given q queries and a multiset A, initially containing only integer 0. There are three types of queries:  "+ x" — add integer x to multiset A. "- x" — erase one occurrence of integer x from multiset A. It's guaranteed that at least one x is present in the multiset A before this query. "? x" — you are given integer x and need to compute the value , i.e. the maximum value of bitwise exclusive OR (also know as XOR) of integer x and some integer y from the multiset A.Multiset is a set, where equal elements are allowed.InputThe first line of the input contains a single integer q (1 ≤ q ≤ 200 000) — the number of queries Vasiliy has to perform.Each of the following q lines of the input contains one of three characters '+', '-' or '?' and an integer xi (1 ≤ xi ≤ 109). It's guaranteed that there is at least one query of the third type.Note, that the integer 0 will always be present in the set A.OutputFor each query of the type '?' print one integer — the maximum value of bitwise exclusive OR (XOR) of integer xi and some integer from the multiset A.ExampleInput10+ 8+ 9+ 11+ 6+ 1? 3- 8? 3? 8? 11Output11101413NoteAfter first five operations multiset A contains integers 0, 8, 9, 11, 6 and 1.The answer for the sixth query is integer  — maximum among integers , , ,  and .
Input10+ 8+ 9+ 11+ 6+ 1? 3- 8? 3? 8? 11
Output11101413
['binary search', 'bitmasks', 'data structures', 'trees', '*1800']