A question about loss_mask layer

[litingsjj]

Hi, I found loss_mask layer have two bottom, about your paper mask_score is 10 * 224 * 224, but the mask_targets, how can I sure 224*224?
name: "loss_mask" type: "SoftmaxWithLoss" #bottom: "mask_score_reshape" bottom: "mask_score" bottom: "mask_targets" top: "loss_mask"