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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Linq;
using System.Collections.Generic;

namespace AtCoder
{
	class Program
	{
		public static void Main()
		{
			var prev = '-';
			foreach(var iChar in IO.Read())
			{
				if(iChar == prev)
				{
					IO.Write("Bad");
					return;
				}
				prev = iChar;
			}
			IO.Write("Good");
		}
	}

	public static class IO
	{
		public static string   Read()							   { return Console.ReadLine(); }
		public static string[] ReadArray(char iSplitter = ' ')	   { return Read().Split(iSplitter); }
		public static int	   ReadInt()						   { return int.Parse(Read()); }
		public static int[]	   ReadIntArray(char iSplitter = ' ')  { return ReadArray().Select(iText => int.Parse(iText)).ToArray(); }
		public static long	   ReadLong()						   { return int.Parse(Read()); }
		public static long[]   ReadLongArray(char iSplitter = ' ') { return ReadArray().Select(iText => long.Parse(iText)).ToArray(); }
		public static char[]   ReadCharArray()					   { return Read().ToCharArray(); }

		public static void Write(string iValue)			  { Console.WriteLine(iValue); }
		public static void Write(int iValue)			  { Console.WriteLine(iValue); }
		public static void Write(IEnumerable<int> iValue) { Console.WriteLine(string.Join(" " , iValue)); }
		public static void Write(long iValue)			  { Console.WriteLine(iValue); }
		public static void Write(decimal iValue)		  { Console.WriteLine(iValue); }
		public static void Write(bool iValue)			  { Console.WriteLine(iValue ? "Yes" : "No"); }
	}

	public static class Util
	{
		public static long Gcd(long i0 , long i1) { return (i0 > i1) ? _Gcd(i0 , i1) : _Gcd(i0 , i1); }
		public static long Lcm(long i0 , long i1) { return (i0 * i1) / Gcd(i0 , i1); }
		public static long ModPow(long iBaseNumber , long iPow , long iModNumber)
		{
			var num = 1L;
			while(iPow != 0)
			{
				if((iPow & 0x1) != 0)
				{
					num = (num * iBaseNumber) % iModNumber;
				}
				iBaseNumber = (iBaseNumber * iBaseNumber) % iModNumber;
				iPow >>= 1;
			}
			return num;
		}

		private static long _Gcd(long i0 , long i1)	{ return (i1 == 0) ? i0 : _Gcd(i1 , i0 % i1); }
	}
}