one is query image from this key is totally arbitrary so why not just do both ways so they actually do both ways and so that is the determine the loss which is L of 2k minus 1 comma 2 k plus L of 2 K comma 2 K minus 1 CD they just flip their order and then you can just use a large large batch gradient descent they use a large optimizer and use bad sizes of 2048 or 4096 on a cloud TPU and and and they're able to perform this optimization really fast and they also train much longer and just like CPC was trained for 500 a