There is a rectangle of size .
This rectangle will be filled with with square tiles without any remaining spaces. You can purchase square tiles as follows:
Find the minimum cost required to fill the entire rectangle with square tiles without any remaining spaces.
The input is given in the following format.
Print the minimum cost required.
If you use square tiles with a side length of , the cost is . However, this is not optimal.
Instead, if you fill it with one square tile with a side length of and two square tiles with a side length of , the cost is . It can be shown that is the minimum cost.
| 3 | 27 | . |
| 4 | 43 | No additional constraints. |