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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"fmt"
	"math"
)

var S string

func main() {
	fmt.Scan(&S)

	for i := 1; i < len(S); i++ {
		if string(S[i]) == string(S[i-1]) {
			fmt.Println("Bad")
			return
		}
	}
	fmt.Println("Good")
}

/*  ----------------------------------------  */

func gcd(x, y uint64) uint64 {
	if x%y == 0 {
		return y
	} else {
		r := x % y
		return gcd(y, r)
	}
}

func combination(x, y int) int {
	return permutation(x, y) / permutation(y, y)
}

func permutation(x, y int) int {
	var ans int = 1
	for i := x - y; 0 < i; i-- {
		ans *= i
	}
	return ans
}

func max(x ...int) int {
	var res int = x[0]
	for i := 1; i < len(x); i++ {
		res = int(math.Max(float64(x[i]), float64(res)))
	}
	return res
}

func min(x ...int) int {
	var res int = x[0]
	for i := 1; i < len(x); i++ {
		res = int(math.Min(float64(x[i]), float64(res)))
	}
	return res
}
func pow(x, y int) int { return int(math.Pow(float64(x), float64(y))) }
func abs(x int) int    { return int(math.Abs(float64(x))) }
func floor(x int) int  { return int(math.Floor(float64(x))) }

type XY struct {
	x int
	y int
}

type SortBy []XY

func (a SortBy) Len() int      { return len(a) }
func (a SortBy) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a SortBy) Less(i, j int) bool {
	if a[i].x == a[j].x {
		return a[i].y > a[j].y
	}
	return a[i].x > a[j].x
}