import sys
# 判断独立子串函数
def jugre(s,l):
    enl = l//2
    for wide in range(3,enl+1):
        for idx in range(0,l//2+1):
            if s.count(s[idx:idx+wide])!=1:
                return 0
    return 1

for line in sys.stdin:
    s = line.strip()
    l = len(s)
    # 判断长度
    if l < 8:
        print('NG')
        continue
    su = [0]*4
    for c in s:
        if c.isdigit():
            su[0]=1
        elif c.islower():
            su[1]=1
        elif c.isupper():
            su[2]=1
        else:
            su[3]=1
    #判断字符
    if sum(su)<3:
        print('NG')
        continue
    #判断子串
    if not jugre(s,l):
        print('NG')
        continue
    print('OK')