Find the only element in an array that appears once while all other elements appear twice (using XOR).

Difficulty: Medium

Phase: 6 · Mixed Logical Challenges

XP Reward: 20 XP

Topics: Mixed Logical Challenges, Medium

Supported Languages: Python, JavaScript, C, C++, Java

Problem Description

Given array of N integers where every element appears twice except one, find that single element using XOR. Input Format: Read input from standard input (stdin). Output Format: Print the result to standard output (stdout).

Constraints

-10^9 <= N <= 10^9

Examples

Example 1

Input: 5 4 1 2 1 2

Output: 4

Explanation: Sample execution for input 5 4 1 2 1 2