Missing Component of Arithmetic Equation

Alice wrote an arithmetic equation on the board in the form $$A \quad op \quad B = C$$ where \(A\), \(B\), and \(C\) are nonnegative integers and \(op\) is one of the four operators: \(+\), \( - \), \(\times\), or \( / \) (where \(/\) indicates integer division).

However, one of the four parts \(A\), \(op\), \(B\), or \(C\) was accidentally erased completely. The erased part is represented by a single question mark ?. Your task is to determine and output the missing part.

Note: It is guaranteed that exactly one part is missing and the given equation is valid. For the missing operator, output the corresponding symbol (one of \(+\), \( - \), \(\times\), or \( / \)).

inputFormat

The input consists of a single line which is an arithmetic equation in the following format:

$$A\quad op\quad B = C$$

Here, each of \(A\), \(B\), and \(C\) is a nonnegative integer and \(op\) is one of \(+\), \( - \), \(\times\), or \( / \) (with \(/\) meaning integer division). Exactly one of the four parts is replaced by a question mark ?, indicating the erased component.

outputFormat

Output the missing component. If the missing component is a number, print the corresponding nonnegative integer. If the missing component is an operator, print the corresponding operator symbol (one of \(+\), \( - \), \(\times\), or \( / \)).

sample

? + 5 = 10

5