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 C# (.NET Core 3.1.201) (judge verdict: Runtime Error)

using System;
using System.Linq;

class Class1
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine().Split(' ').Select(long.Parse).ToList();
        long A = input[0];
        long B = input[1];
        long C = input[2];
        long D = input[3];

        long result = 0;

        for (long i = A; i <= B; i++)
        {
            if (i % C == 0 || i % D == 0)
            {
                continue;
            }

            result++;
        }

        long numb = B - (B / C + B / D) + (B / (lcm(C, D)));
        long numa = (A - 1) - ((A - 1) / C + (A - 1) / D) + ((A - 1) / lcm(C, D));

        Console.WriteLine(numb - numa);
    }

    // 最大公約数
    static long gcd(long a, long b)
    {
        if (a % b != 0)
        {
            return gcd(b, a % b);
        }
        else
        {
            return b;
        }
    }

    static long lcm(long a, long b)
    {
        return a * b / gcd(a, b);
    }
}