Remove 1 items
Insert "e,Uniq"
Insert "a,Uniq"
Keep 3 items
Insert "a,Uniq"
Insert "b,Uniq"
Keep 2 items
Insert "f,Uniq"
Keep 3 items
Insert "d,Burn"
Insert "b,Burn"
Insert "d,Burn"
Insert "c,Burn"
Insert "c,Burn"
Insert "b,Burn"
Keep 5 items