Problem:
Score : 100 points

Problem Statement

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.

Sample Input 1

5 7 5

Sample Output 1

7

This is the same case as the one in the statement.

Sample Input 2

1 1 7

Sample Output 2

7

In this case, C is the one we seek.

Sample Input 3

-100 100 100

Sample Output 3

-100

Solution in Python (3.4.3) (judge verdict: Runtime Error)

H, W = map(int, input().split())
table = []
table.append(list("_" * (W + 2)))
for _ in range(H):
    table.append(list("_" + input() + "_"))
table.append(list("_" * (W + 2)))

for h in range(1, H + 1):
    for w in range(1, W + 1):
        if table[h][w] == "#":
            continue
        count = 0
        for _h in [-1, 0, +1]:
            for _w in [-1, 0, +1]:
                print(h + _h, w + _w)
                if table[h + _h][w + _w] == "#":
                    count += 1
        table[h][w] = str(count)

for h in range(1, H + 1):
    print("".join(table[h]).replace("_", ""))