除法很重要，没想到现在减法也这么重要
https://link.storjshare.io/raw/jxdvshymauzglqp5x5ihb2cpvk7a/production/9c01ac45faa15b373858702b6e67d1bcfec7e8d7c8c60e84824ebdee7e07b329.JPG
https://link.storjshare.io/raw/jujacn75ayer6ker5nsmkjcej4kq/production/262500cdcae1f4c25d47e23c4a031bcdf5870bda50d0e1e41779d47f76372dda.JPG