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
ayushgupta1997: 2017-05-28 11:00:10

EAsy man took the mistook array size as 10^5 instead of 5*10^5 costed me sigsev...use xor basics :)

sagnik_66: 2017-05-21 08:09:59

Easy!

anurag_tangri: 2017-03-25 17:46:01

CAKEWALK :)

ameyanator: 2017-03-20 06:23:42

Great problem to learn the xor gate!! :')

rohit9934: 2017-03-07 17:04:41

MF semicolons give me 3 WA. Simple Use of XOR,Learnt XOR.

nilabja16180: 2017-02-15 19:01:29

AC in one GO!

Fodor Gabor: 2017-01-31 19:17:35

Python gets TLE, even for O(N) solution.
For Java, using Scanner for I/O also gives TLE, use BufferedReader instead.
For C++, see comments.

singhaljoy: 2017-01-22 12:10:18

Use property of XOR, AC in 1 go!!!

shantanu_sarin: 2017-01-20 13:55:34

cin cout gives TLE
use scanf printf
cost me 4 WA

scorpion_ajay: 2017-01-12 12:02:12

easiest till :p


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