I just solved this problem
I only changed the class_num value and did not change 85 * 3
So I changed 85 * 3 to 13 * 3 and it run successly
85*3 → (8+5)*3
Thank you so much for your reply. 
I just solved this problem
I only changed the class_num value and did not change 85 * 3
So I changed 85 * 3 to 13 * 3 and it run successly
85*3 → (8+5)*3
Thank you so much for your reply.