from operator import mul
from functools import reduce

n, m = map(int, input().split())
mod = 1000000007


def cmb(n,r):
    r = min(n-r,r)
    if r == 0: return 1
    over = reduce(mul, range(n, n - r, -1))
    under = reduce(mul, range(1,r + 1))
    return over // under


ans = 0
for i in range(n, m+1):
    ans += cmb(i, n) % mod
    ans %= mod

print(ans)