Every value in the array appears exactly three times except for a single value that appears exactly once. Find that value.
Input format
Line 1: an integer n.
Line 2: n space-separated non-negative integers.
Output format
One line: the value that appears exactly once.
Constraints
- 1 <= n <= 100000, n = 3m + 1 for some m >= 0
- 0 <= each value <= 1000000000