num_songs=int(input()) orders=input() SHOW=1 p=1 for order_i in orders:     if order_i=="U":         SHOW-=1         if SHOW<=0:             SHOW=num_songs             p=4         else:             p-=1     if order_i=="D":         SHOW+=1         if SHOW>10:             SHOW=1             p=1         else:             p+=1 if p==1:     print(SHOW,SHOW+1,SHOW+2,SHOW+3) elif p==2:     print(SHOW-1,SHOW,SHOW+1,SHOW+2) elif p==3:     print(SHOW-2,SHOW-1,SHOW,SHOW+1) elif p==4:     print(SHOW-3,SHOW-2,SHOW-1,SHOW) print(SHOW) 第一道编程，哪错了？