def judge(a):
    if len(a) > 1 and a[0] == "0": return False

    for c in a:
        if ord("0") <= ord(c) <= ord("9"): pass
        else: return False

    if int(a) > 12345: return False
    return True


a = input()
b = input()

if judge(a) and judge(b): print("OK")
else: print("NG")