a, b = gets, gets

if a =~ /[a-zA-z]/ || b =~ /[a-zA-Z]/ then
  puts "NG"
elsif a =~ /^0[0-9]+/ || b =~ /^0[0-9]+/ then
  puts "NG"
else
  a = a.to_i
  b = b.to_i
  if a > 12345 || b > 12345 then
    puts "NG"
  else
    puts "OK"
  end
end