Find the number of positive integers solutions $(x_1, x_2,..., x_k)$ for the following equation:
$$
\begin{equation}
\begin{cases}
x_1 < x_2 < ... < x_k \\\\
x_1 + x_2 + ... + x_k=n
\end{cases}
\end{equation}
$$
### Input
- A single line contains two integers $n, k$.
### Output
- Print the number of solutions, modulo $10^9+7$.
### Constraints
- $1 \le n \le 10^9$.
- $1 \le k \le 5$.
### Example
Input:
```
10 3
```
Output:
```
4
```