def isInt(string):
	if len(string)>=2 and string[0]=="0":
		return False
	for i in string:
		if i not in ["1","2","3","4","5","6","7","8","9","0"]:			
			return False
	return True


if __name__=="__main__":
	a=input()
	b=input()
	if isInt(a) and isInt(b):
		if 0<=int(a)<=12345 and 0<=int(b)<=12345:
			print("OK")
		else:
			print("NG")
	else:
		print("NG")