def f(a)
	if a[0]=="0" && a.size>1 then
		return false
	elsif a.scan(/\D/).size>0 then
		return false
	elsif (0<=a.to_i) && (a.to_i<=12345) then
		return true
	else
		return false
	end
end

a=gets.chomp
b=gets.chomp
puts (f(a)&&f(b))?"OK":"NG"