excel if 和lookup函数的使用

if(j11>92,“92”，if(91>=j11>=90,"92",if(89>=j11>=88,"90",if(87>=j11>=71,"j11",if（70>=j11>=65,"70",if(64>=j11>=60,"68",if(59>=j11>=55,"64",if(54>=j11>=50,"62",if(49>=j11>=45,"60",if(45>j11,"j11")))))))))
lookup(j11,{0,"j11",44;45,"60",49;50,"62",54;55,"64",59;60,"68",64;65,"70",70;71,"j11",87;88,"90",89;90,"92",91;92,"j11"})如上述程序，我想得到92以上记为原数，90-91记为92，88-89记为90，70-87记为原数，65-70记为70，60-64记为68，55-59记为64，50-54记为62，45-49记为60，45以下为原数。其中j11为原数据存储列

excel2013提示if函数嵌套层数超过限制，而lookup函数有误，求大神帮忙