p03573 AtCoder Beginner Contest 075 - One out of Three
You 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.

Input

Input is given from Standard Input in the following format:


A B C


Output

Among A, B and C, print the integer that is different from the rest.

Examples

Input

5 7 5


Output

7


Input

1 1 7


Output

7


Input

-100 100 100


Output

-100
```python
a,b,c=map(int,input().split())
print((b==c)*a+(c==a)*b+(a==b)*c)
```