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: Runtime Error)

use std::str::FromStr;
use std::io;

fn whitespace_second() -> (usize, usize) {
    let stdin = io::stdin();
    let mut buf = String::new();
    stdin.read_line(&mut buf).ok();
    let mut it = buf.split_whitespace().map(|n| usize::from_str(n).unwrap());
    (it.next().unwrap(), it.next().unwrap())
}

fn main() {
    let (n, l) = whitespace_second();
    let mut e: usize = 1000000;
    let mut res: usize = 0;
    for i in 1..(n + 1) {
        let a = l + i - 1;
        e = if (a > 0) && (e >= a) {
             a 
        } else {
             e
        };
        res = res + a;
    }
    res = res - e;
    println!("{}", res);
}