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
theabd123: 2018-05-30 16:14:41

THE POWER OF XOR

incomplet_: 2018-04-18 07:47:36

Don't using cin, cout, even with optimal algorithm this result in TLE

pratikshit: 2018-03-18 15:31:43

first time used XOR in a problem

zephyr_96: 2018-03-01 12:28:47

Better add JAVA to your list of unsupported languages.

ayusofayush: 2018-02-24 11:10:15

this problem teaches you the use of xor(^) operator

abhijeetgurle: 2018-02-10 05:59:24

Even if you write O(nlogn) solution it will get accepted using fast I/O.

amankriet: 2018-01-22 13:23:40

Last edit: 2018-01-22 13:24:32
sanyam19: 2018-01-09 16:03:42

learnt a vry gud concept frm ths Q.... :)

karthik1997: 2018-01-05 15:51:16

Man , int and xor are enough ! O(1) space is enough !

amankumarjha: 2018-01-01 11:27:01

Taught me to use xor and %llu


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