type treenode =
{
mutable left: treenode option;
mutable right: treenode option;
value: int;
}
;;

let bst = {left = None; right = None; value = 5};;

let rec insert_to_bst value root : unit =
if value.value >= root.value then
if root.right = None then
begin
root.right <- (Some value);
end
else
insert_to_bst value root.right
else
if root.left = None then
begin
root.left <- (Some value)
end
else
insert_to_bst value root.left;;