#!/usr/bin/env python3
M = 1000000007

###
if __name__ == '__main__':
    a, b = map(int, input().split())
    fac = [None] * (b+1)
    fac[0] = 1
    for i in range(b):
        fac[i+1] = fac[i] * (i+1) % M
    inv = [None] * (b+1)
    inv[b] = pow(fac[b], M-2, M)
    for i in reversed(range(b)):
        inv[i] = inv[i+1] * (i+1) % M
    res = 0
    for i in range(a, b+1):
        res += fac[i] * inv[i-a] * inv[a] % M
        res %= M
    print(res)