- Time limit: 1.00 s
- Memory limit: 512 MB
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
- $1 \le n,m \le 10^6$
Input:
3 2
Output:
6