URI Online Judge | 2091

Lonely Number

By Gabriel Duarte, UNIFESO BR Brazil

Timelimit: 1

You will be given an array of N numbers, where everyone will be in pairs. But one of those numbers ended up without peer, you can identify what is that number?

For example, A = {1, 1, 3, 3, 5, 5, 5}, the number stood alone was 5.

Input

The input consists of several test cases. Each test case is composed of a line having an integer N (1 ≤ N < 10^5), followed by N number A (1 ≤ A ≤ 10^12).

Output

For each test case print only the number that stood alone. It is guaranteed that only one number is alone

Input Sample Output Sample

5
1 3 4 3 1
3
1 1 1
7
1 1 3 3 5 5 5
0

4
1
5