N,M = map(int,input().split())
P = 10 ** 9 + 7
fact = [1] * (M+1)
fact_inv = [1] * (M+1)
for i in range(2,M+1):
    fact[i] = fact[i-1] * i % P
fact_inv[-1] = pow(fact[-1],P-2,P)
for i in range(M-1,1,-1):
    fact_inv[i] = fact_inv[i+1] * (i+1) % P
def comb(n,k):
    return fact[n] * fact_inv[k] % P * fact_inv[n-k] % P
ans = 0
for i in range(M-N+1):
    ans = (ans + comb(N+i,N)) % P
print(ans)