Problem Statement
There is a building with $n$ rooms, numbered $1$ to $n$.
We can move from any room to any other room in the building.
Let us call the following event a move: a person in some room $i$ goes to another room $j~ (i \neq j)$.
Initially, there was one person in each room in the building.
After that, we know that there were exactly $k$ moves happened up to now.
We are interested in the number of people in each of the $n$ rooms now. How many combinations of numbers of people in the $n$ rooms are possible?
Find the count modulo $(10^9 + 7)$.
Constraints
- All values in input are integers.
$3 \leq n \leq 2 \times 10^5$$2 \leq k \leq 10^9$
Input
Input is given from Standard Input in the following format:
n k
Output
Print the number of possible combinations of numbers of people in the $n$ rooms now, modulo $(10^9 + 7)$.
样例
3 2
10
200000 1000000000
607923868
15 6
22583772
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