Problem Description

Takahashi thought he wrote a program to output A+B in a programming contest, but he started to feel uncertain whether he actually wrote a program to output A-B. Takahashi accidentally deleted the program and only has the input and output left. Determine whether Takahashi wrote a program to output A+B, A-B, either of them, or neither.

If only one of the possibilities (A+B or A-B) can be true, then judge that Takahashi wrote that program. For example, if the input 1 1 results in an output of 2, then A+B is possible but A-B is not, so judge that Takahashi wrote A+B.

Input Format

The input is given from the standard input in the following format:

$ A $ $ B $ $ C $

• Integers representing the input to Takahashi's program, $A,\ B\ (0≦A,B≦100)$, and the output of Takahashi's program, $C\ (0≦C≦100)$, are given separated by spaces.

Output Format

If it is clear that Takahashi wrote A+B, output +; if it is clear that he wrote A-B, output -; if either possibility exists, output ?; if neither is possible, output !. End the output with a newline.

Sample Input and Output

Sample Input #1

1 0 1

Sample Output #1

?

Sample Input #2

1 1 2

Sample Output #2

+

Sample Input #3

1 1 0

Sample Output #3

-

Sample Input #4

1 1 1

Sample Output #4

!

Notes/Hints

None

见题面 Input 部分

见题面 Output 部分