Problems
Odd number
Odd number
Find the number that appears in the sequence only once.
Input
First line contains positive integer n (n < 500000). Then n positive integers follow (delimited with space) each less than 106.
Output
In input sequence only one number x is repeated odd times. Others have even number of occurrences. You should output x.
Input example #1
9 3 1 2 2 17 1 3 17 3
Output example #1
3
Input example #2
5 12 13 14 13 12
Output example #2
14