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).


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


Output one positive integer on pyani, which appeared once.



Output: 8

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

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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.

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

bani_raheja: 2017-12-29 16:07:26

what is the point of having such problems if you want people to use Fast I/O? :3

sai__teja_01: 2017-11-29 19:29:18

easy problem ,if ur facing TLE use scanf and printf instead cin and cout ,if ur using c++

hitesh87: 2017-10-05 22:42:39

Learned to use xor.AC in many goes;p

vishesh197: 2017-09-23 17:22:15

just use xor as x^x=0 and x^0=x

Added by:Efim
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64