## Description:

Anthony has collected a large amount of sticks for manufacturing chopsticks. In order to simplify his job, he wants to fetch two equal-length sticks for machining at a time. After checking it over, Anthony finds that it is always possible that only one stick is left at last, because of the odd number of sticks and some other unknown reasons. For example, Anthony may have three sticks with length 1, 2, and 1 respectively. He fetches the first and the third for machining, and leaves the second one at last. Your task is to report the length of the last stick.

## Input:

The input file will consist of several cases.

Each case will be presented by an integer n (1<=n<=100, and n is odd) at first. Following that, n positive integers will be given, one in a line. These numbers indicate the length of the sticks collected by Anthony.

The input is ended by n=0.

## Output:

For each case, output an integer in a line, which is the length of the last stick.

## Sample Input:

3

1

2

1

0

## Sample Output:

2

## Note:

本题由旧版NOJ导入，来源：第九届中山大学程序设计竞赛预选题