Problem:
Score : 100 points

Problem Statement

Joisino wants to evaluate the formula "A op B".
Here, A and B are integers, and the binary operator op is either + or -.
Your task is to evaluate the formula instead of her.

Constraints

1≦A,B≦10^9

op is either + or -.

Input

The input is given from Standard Input in the following format:

A op B

Output

Evaluate the formula and print the result.

Sample Input 1

1 + 2

Sample Output 1

3

Since 1 + 2 = 3, the output should be 3.

Sample Input 2

5 - 7

Sample Output 2

-2

Solution in PHP7 (7.0.15) (judge verdict: Accepted)

<?php

$input = fgets(STDIN);

if (!preg_match('/([\d]+)\s([+\-])\s?([\d]+)?/u', $input, $match)) {
    echo '入力値エラー';
    return;
}

$a = (int) $match[1];
$b = (int) $match[3];

$op = $match[2];

if ($op === '+') {
    echo $a + $b;
} elseif ($op === '-') {
    echo $a - $b;
}