smooth = 1.
                intersection = tf.reduce_sum(flat_logits * flat_labels)
                dice_score = (2 * intersection + smooth) / (
                            tf.reduce_sum(flat_labels) + tf.reduce_sum(flat_logits) + smooth)
                dice_loss = 1 - dice_score
                cross_entropy_loss = tf.reduce_mean(
                    tf.nn.softmax_cross_entropy_with_logits_v2(logits=flat_logits, labels=flat_labels))
                loss = dice_loss + cross_entropy_loss