Working_day__c
    false
    IF(text(month(Evaluation_date__c)) = "4",21, 
 IF(text(month(Evaluation_date__c)) = "5",20, 
 IF(text(month(Evaluation_date__c)) = "6",20, 
 IF(text(month(Evaluation_date__c)) = "7",23, 
 IF(text(month(Evaluation_date__c)) = "8",21, 
 IF(text(month(Evaluation_date__c)) = "9",22, 
 IF(text(month(Evaluation_date__c)) = "10",17, 
 IF(text(month(Evaluation_date__c)) = "11",21, 
 IF(text(month(Evaluation_date__c)) = "12",22, 
 IF(text(month(Evaluation_date__c)) = "1",20, 
 IF(text(month(Evaluation_date__c)) = "2",16, 
 IF(text(month(Evaluation_date__c)) = "3",23,0) 
 ) 
 ) 
 ) 
 ) 
 ) 
 ) 
 ) 
 ) 
 ) 
 ))
    BlankAsZero
    
    18
    false
    0
    false
    Number
    false