from functools import lru_cache
import math


class Modint:

    MOD = int(1e9+7)

    def __init__(self, value: int) -> None:
        self.num = int(value) % self.MOD

    def __str__(self) -> str:
        return str(self.num)

    __repr__ = __str__

    def __add__(self, __x):
        if isinstance(__x, Modint):
            return Modint((self.num + __x.num))
        return Modint(self.num + __x)

    def __sub__(self, __x):
        if isinstance(__x, Modint):
            return Modint(self.num - __x.num)
        return Modint(self.num - __x)

    def __mul__(self, __x):
        if isinstance(__x, Modint):
            return Modint(self.num * __x.num)
        return Modint(self.num * __x)

    __radd__ = __add__
    __rmul__ = __mul__

    def __rsub__(self, __x):
        if isinstance(__x, Modint):
            return Modint(__x.num - self.num)
        return Modint(__x - self.num)

    def __pow__(self, __x):
        if isinstance(__x, Modint):
            return Modint(pow(self.num, __x.num, self.MOD))
        return Modint(pow(self.num, __x, self.MOD))

    def __rpow__(self, __x):
        if isinstance(__x, Modint):
            return Modint(pow(__x.num, self.num, self.MOD))
        return Modint(pow(__x, self.num, self.MOD))

    def __truediv__(self, __x):
        if isinstance(__x, Modint):
            return Modint(self.num * pow(__x.num, self.MOD - 2, self.MOD))
        return Modint(self.num * pow(__x, self.MOD - 2, self.MOD))

    def __rtruediv__(self, __x):
        if isinstance(__x, Modint):
            return Modint(__x.num * pow(self.num, self.MOD - 2, self.MOD))
        return Modint(__x * pow(self.num, self.MOD - 2, self.MOD))


def main():
    N, M = map(int, input().split())

    sum_ = Modint(0)
    # for num in range(N, M+1):
    #     current = math.factorial(num) // math.factorial(num-N)
    #     sum_ += current
    #     print(current)
    current = -1
    for num in range(N, M+1):
        if current == -1:
            current = Modint(math.factorial(num))
        else:
            current = current * num / (num - N)

        sum_ += current

    print(sum_ / math.factorial(N))


if __name__ == "__main__":
    main()