Given four positive integers S,n,L,H. Count the number of integer solutions of the following equation:
x1+x2+...+xn=S
that satisfy:
L≤xi≤H for all i such that (1≤i≤n)
### Input
- Consists of four integers S,n,L,H (0≤L≤H≤S,1≤n≤S≤106) .
### Output
- Print the answer modulo 109+7.
### Và dụ
Input:
5302
Output:
3
