import Data.Char

isNum [] = True
isNum (a:as) = if (isDigit a) then (isNum as) else False

leadingZero [a] = False
leadingZero (a:as) = (a == '0') && ((head as) == '0')

judge a = ((isNum a) && ((read a) <= 12345)) && (not (leadingZero a))

f a b = if j == True then "OK" else "NG"
	where ja = judge a
	      jb = judge b
	      j = (ja == True) && (jb == True)

main = do
  a <- getLine
  b <- getLine
  putStrLn $ f a b