a=input().strip()
def solve(a):
    stack=[]
    for i in range(len(a)):
        if a[i]=='a':
            stack.append(a[i])
        elif a[i]=='b':
            if not stack or stack[-1]!='a' :
                return "Bad"
            else:
                stack.pop()
    if not stack:
        return "Good"
    else:
        return "Bad"


print(solve(a))