# The Plank

You want to construct a long plank using smaller wooden pieces. There are three kinds of pieces of lengths $1$, $2$ and $3$ meters respectively, each which you have an unlimited number of. You can glue together several of the smaller pieces to create a longer plank.

If the plank should have length $n$ meters, in how many different ways can you glue pieces together to get a plank of the right length?

## Input

The first and only line of input contains an integer $n$ ($1 \le n \le 24$), the length of the new plank.

## Output

Output a single integer – the number of ways you can glue together a plank of length $n$ meters.

## Scoring

Your solution will be tested on a set of test groups, each worth a number of points. To get the points for a test group you need to solve all test cases in the test group. Your final score will be the maximum score of a single submission.

Group |
Points |
Constraints |

$1$ |
$33$ |
$n \le 10$ |

$2$ |
$67$ |
No additional constraints |

Sample Input 1 | Sample Output 1 |
---|---|

4 |
7 |