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CSES Problem Set

Distributing Apples


Task | Statistics


CSES - Distributing ApplesCSES - Distributing Apples

Time limit:1.00 s Memory limit:512 MB

There are $n$ children and $m$ apples that will be distributed to them. Your task is to count the number of ways this can be done.

For example, if $n=3$ and $m=2$, there are $6$ ways: $[0,0,2]$, $[0,1,1]$, $[0,2,0]$, $[1,0,1]$, $[1,1,0]$ and $[2,0,0]$.

Input

The only input line has two integers $n$ and $m$.

Output

Print the number of ways modulo $10^9+7$.

Constraints
Example

Input:
3 2

Output:
6