原始2100左右
X+X*39.3%=3456,X(1+39.3%)=3456,X=3456/(1+39.3%)=
官|网|不|是|有|内|个|计|算|器|么| ~~我|数|学|不|好| 这|个|算|不|来| 嘎|嘎|~~