a=input()
b=input()


if a.isnumeric() and b.isnumeric():
    if int(a) > 12345 or int(b) > 12345:
        print("NG")
    elif (a[0]=="0" and a!="0") or (b[0]=="0" and b!="0"):
        print("NG")
    else:
        print("OK")
else:
    print("NG")