Invisible

This is an interactive problem.

You are given an array $a\_1, \ldots, a\_n$ of $n$ integers. You have to process queries of two types:

• "1 $x$ $y$": change value of $a\_x$ to $y$.
• "2 $l$ $r$": find and print a number that occurs an odd number of times in the segment $a\_l, a\_{l + 1}, \ldots, a\_r$, or determine that there is no such number and print $-1$ instead. If there are several suitable numbers, you can output any of them.