OLOLO - Onotole needs your help


Onotole has a lot of pyani. Each pyani has a number, writing on it. Pyanis with equal numbers are indistinguishable. Onotole knows everything, so, he knows that each pyani appeared twice, and only one pyani is unique. He wants to get вздръжни эффект, and he needs the unique pyani. Given the list of pyanis denote which one of them appeared once (it is guaranteed that other pyanis appeared twice).

Input

First line of input contains number of pyanis N <= 500 000. Next N lines contain a single positive integer 1 <= Pi <= 10^9.

Output

Output one positive integer on pyani, which appeared once.

Example

Input:
3
1
8
1

Output: 8

Onotole has found not optimal AC algorithms, so all solutions will be rejudged. He is watching you.


hide comments
MishThi: 2015-08-04 11:05:03

1. Really good question. Taught me about the XOR operator.. :D
2. Same solution gave AC in "C" but TLE in "Python 2.7.10" :(

Akshay Aradhya: 2015-07-18 22:38:58

@Arnab Fast I/O Not required in C++

Akshay Aradhya: 2015-07-18 22:38:25

Funniest Problem Statement Ever. You gotta love Russians and their sense of humour :D

Piyush Kumar: 2015-06-24 12:00:49

Do not use cin>>. Use scanf.

Arnab Mitra: 2015-05-20 22:31:10

In case you are doing this question using a sort, please use fast I/O


Added by:Efim
Date:2010-11-04
Time limit:0.134s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64