# coding:utf-8
        #集合差
        
        # set difference
        x = {"apple", "banana", "cherry"}
        y = {"google", "microsoft", "apple"}
        z = x.difference(y)
        print(z)
        
        b = y.difference(x)
        print(b)
        
        #Remove the items that exist in both sets
        x = {"apple", "banana", "cherry"}
        y = {"google", "microsoft", "apple"}
        x.difference_update(y) 
        print(x)