Given an array with 2n+1 integers, n elements appear twice in arbitrary places in the array and single integer appears only once somewhere inside. Find that lonely integer with O(n) operations and O(1) extra memory.
Input format:
Output format:
Integer that occurs only once in the array.
Examples:
Input :
2
4
3
8
4
8
Output :
3
3 occurs only once in the array.