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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nonushikhar: 2016-03-23 15:54:44

simple sort method accepted :|

syed_tanveer: 2016-02-22 16:49:44

cout and cin gave a TLE . :/

abc_c: 2016-02-07 08:14:18

Didn't know about use of XOR this way.

hamcom1212: 2016-01-26 07:15:01

I used hash map in c++ but get TLE .. :(

prateekmathur1991: 2016-01-12 11:34:50

Got AC with Java... :) Needs fast I/O though...

dokz: 2016-01-06 10:25:01

The problem seems to be impossible in C# \ Java.

sarthak_8: 2016-01-02 20:19:44

Why did not anybody do it with C++ Maps?

Timmy Jose: 2015-12-12 16:05:59

For people using C++ streams, try setting ios_base::sync_with_stdio(false) in your program before doing any input operations. This should help.

Timmy Jose: 2015-12-12 16:04:40

@Sumit Suthar

Mate, you really shouldn't leave the answer for other people to accidentally stumble upon. Thankfully I figured this out and then checked the comments (as I always do now - SPOJ really should have the comments collapsed, by the way). If SPOJ had a feature to report people, I'd report you in a heartbeat. Stop being a tool.

Timmy Jose: 2015-12-12 16:03:07

For all people, complaining, this is a simple but beautiful problem. It's a pretty simple one, but I love its requirement for one to think and figure out the simple way!

Last edit: 2015-12-12 16:06:27

Added by:Efim
Time limit:1s
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Memory limit:1536MB
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