import re
A = input()
B = input()
a = re.match('(.*[A-Za-z]+.*)|(^0+.+)',A)
b = re.match('(.*[A-Za-z]+.*)|(^0+.+)',B)
if a or b:
	print('NG')
else:
	if 0 <= int(A) <= 12345 and 0 <= int(B) <= 12345:
		print('OK')