公式中countif前的“1/”怎么理解?=INT(SUM(1/IF(COUNTIF($B$2:$B$14,IF($A$2:$A$14=F2,$B$2:$B$14,""))=0,1000,(COUNTIF($B$2:$B$14,IF($A$2:$A$14=F2,$B$2:$B$14,""))))))公式中的=0,1000怎么理解?