Find your present!

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 3579    Accepted Submission(s): 2386

Problem Description

In the new year party, everybody will get a "special present".Now it‘s your turn to get your special present, a lot of presents now putting on the desk, and only one of them will be yours.Each present has a card number on it, and your present‘s card number will be the one that different from all the others.For example, there are 5 present, and their card numbers are 1, 2, 3, 2, 1.so your present will be the one with the card number of 3, because 3 is the number that different from all the others.

Input

The input file will consist of several cases.   Each case will be presented by an integer n (1<=n<=200, and n is odd) at first. Following that, n positive integers will be given in a line. These numbers indicate the card numbers of the presents.n = 0 ends the input.

Output

For each case, output an integer in a line, which is the card number of your present.

Sample Input

5

1 1 3 2 2

3

1 2 1

0

Sample Output

3

2

位运算：

 1 #include <iostream>
 2 using namespace std;
 3
 4 int main(){
 5     int n, num;
 6     while(cin >> n && n != 0){
 7         int ans = 0;
 8         for(int i = 0; i < n; i++){
 9             cin >> num;
10             ans = ans ^ num;
11         }
12         cout << ans << endl;
13     }
14     return 0;
15 }