thisset = {"apple", "banana", "cherry"}
print(thisset)

for x in thisset:  
  print(x)

print("banana" in thisset) # checking


thisset.add("orange") #adding new element to set
print(thisset)

thisset.add("orange")
print(thisset)

thisset.remove("orange") #removing
print(thisset)

print(len(thisset)) 

# https://informatics.msk.ru/mod/statements/view3.php?id=11544&chapterid=112475