#yuki_446

def f(s):
 if len(s)>1 and s[0]=='0':
  return False
 if s.isdigit()==False:
  return False
 if int(s)>12345:
  return False
 return True
  
a=raw_input()
b=raw_input()
if f(a) and f(b):
 print 'OK'
else:
 print 'NG'