URI Online Judge | 2091
# Lonely Number

**Timelimit: 1**

By Gabriel Duarte, UNIFESO Brazil

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.

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).

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 |
4 |