import re
a,b = input(),input()
s = "NG"
if (re.fullmatch(r'[1-9][0-9]*',a) or a=='0') and (re.fullmatch(r'[1-9][0-9]*',b) or b=='0'):
	if int(a)<12346 and int(b)<12346:
		s = "OK"
print(s)