# Grasshopper

Very easy

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

Grasshopper lives in the teacher's room. It likes to jump on one dimensional checkerboard. The length of the board is n cells. To its regret, it can jump only on 1, 2, ..., k cells forward.

Once teachers wondered in how many ways a grasshopper can reach the last cell from the first one. Help them to answer this question.

## Input

Two integers n and k (1 ≤ n ≤ 30, 1 ≤ k ≤ 10).

## Output

Print the number of ways for grasshopper to leap from the first cell to the last.

## Examples

Input #1

Answer #1

Input #2

Answer #2

Input #4

Answer #4

Input #8

Answer #8

Submissions 8K

Acceptance rate 46%