Problem:
Score : 100 points

Problem Statement

The door of Snuke's laboratory is locked with a security code.

The security code is a 4-digit number. We say the security code is hard to enter when it contains two consecutive digits that are the same.

You are given the current security code S. If S is hard to enter, print Bad; otherwise, print Good.

Constraints

S is a 4-character string consisting of digits.

Input

Input is given from Standard Input in the following format:

S

Output

If S is hard to enter, print Bad; otherwise, print Good.

Sample Input 1

3776

Sample Output 1

Bad

The second and third digits are the same, so 3776 is hard to enter.

Sample Input 2

8080

Sample Output 2

Good

There are no two consecutive digits that are the same, so 8080 is not hard to enter.

Sample Input 3

1333

Sample Output 3

Bad

Sample Input 4

0024

Sample Output 4

Bad

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

<?php
# A - Security

$array = str_split((fgets(STDIN)));
$key = $array[0];
for ($i = 1; $i < 4; $i++) {
    if ($array[$i] == $key) {
        echo 'Bad' . PHP_EOL;
        exit;
    } else {
        $key = $array[$i];
    }
}
echo 'Good' . PHP_EOL;