## Goal

You have a number `N` of magic stones each of which has a level with a positive integer value.

The stones are very heavy and cumbersome to carry around.

Luckily you can use your magic powers to combine two stones of level i to form a single stone of level i+1.

Use your power to minimise the number of stones that you have.
Input

**Line 1:** An integer `N` for the number of magic stones you have.

**Line 2:** `N` space separated integer values

Output

**Line 1:** The minimum number of stones you can have.