A:>bst
Enter numbers to insert, -1 when you are done: 3 2 4 1 -1
    4
3
    2
        1
Enter numbers to search for, -1 when you are done: 3 4 0 -1
3: found
4: found
0: not found

Enter numbers to remove, -1 when you are done: 3 -1
    4
2
    1
More (y/n)? n

A:>