B"There is an array a of 2^{30} integers, indexed from 0 to 2^{30}-1 . Initially, you know that 0 <= q a_i < 2^{30} ( 0 <= q i < 2^{30} ), but you do not know any of the values. Your task is to process queries of two types: Note that the queries are encoded. That is, you need to write an online solution. The first line contains a single integer q ( 1 <= q q <= q 2 cdot 10^5 ) -- the number of queries. Each of the next q lines describes a query. It contains one integer t ( 1 <= q t <= q 2 ) -- the type of query. The given queries will be encoded in the following way: let last be the answer to the last query of the second type that you have answered (initially, last = 0 ). If the last answer was -1 , set last = 1 . and, if l > r , swap l and r . This means you got an update that the bitwise xor of the subarray [l, r] is equal to x (notice that you need to ignore updates that contradict previous updates). and, if l > r , swap l and r . For the given query, you need to print the bitwise xor of the subarray [l, r] . If it is impossible to know, print -1 . Don't forget to change the value of last . It is guaranteed there will be at least one query of the second type. After every query of the second type, output the bitwise xor of the given subarray or -1 if it is still impossible to know. In the first example, the real queries (without being encoded) are: In the second example, notice that after the first two updates we already know that a_5 oplus a_6 = 12 , so the third update is contradicting, and we ignore it. "...