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

 

 找不同。。。。用数组超时，只得位运算

1 #include
     
       2 using namespace std; 3 int main() 4 { 5     int N=0,result=0,num=0; 6     while(true) 7     { 8         cin>>N; 9         if(N==0)10             break;11         else12         {13             for(int i=0; i
      
       >num;16                 result=result^num;17             }18             cout<
       
        <