if len(s)<=8:
        return 'NG'
    li = [0,0,0,0]
    for i in s:
        if i.isdigit():
            li[0]=1
        elif i.islower():
            li[1]=1
        elif i.isupper():
            li[2]=1
        else:
            li[3]=1
    if sum(li)<3:
        return "NG"
    for i in range(len(s)-2):
        x = s[i:i+3]
        if x in s[i+3:]:
            return "NG"
    return "OK"
while 1:
    try:
        print(func(input()))
    except:
        break