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 Rust (1.15.1) (judge verdict: Accepted)

use std::io::*;

fn read_bytes(length: usize, skip_next: bool) -> Vec<u8> {
    let mut bytes = vec![0; length];
    let stdin = stdin();
    let mut stdin = stdin.lock();
    stdin.read_exact(&mut bytes).unwrap();
    if skip_next {
        stdin.bytes().next();
    }
    bytes
}

fn println<T: ToString>(s: T) {
    println!("{}", s.to_string());
}

// ------------------------------------------------------------------------

fn main() {
    let s = read_bytes(4, false);

    for pair in s.windows(2) {
        if pair[0] == pair[1] {
            println("Bad");
            return;
        }
    }

    println("Good");
}