
Score : 100 points
Problem StatementYou are given three integers, A, B and C.
Among them, two are the same, but the remaining one is different from the rest.
For example, when A=5,B=7,C=5, A and C are the same, but B is different.
Find the one that is different from the rest among the given three integers.  
Constraints
-100 \leq A,B,C \leq 100 
A, B and C are integers.
The input satisfies the condition in the statement.
InputInput is given from Standard Input in the following format:  
A B C
OutputAmong A, B and C, print the integer that is different from the rest.
Sample Input 15 7 5
Sample Output 17
This is the same case as the one in the statement.
Sample Input 21 1 7
Sample Output 27
In this case, C is the one we seek.
Sample Input 3-100 100 100
Sample Output 3-100
