N,M = map(int,input().split())
MOD = 10**9+7
A = [1]*(M+1)
for i in range(2,M+1):
    A[i] = (A[i-1]*i)%MOD
B = [1]*(M+1)
B[M] = pow(A[M],MOD-2,MOD)
for i in range(M-1,1,-1):
    B[i] = (B[i+1]*(i+1))%MOD
def comb(n,k):
    if k<0 or k>n:
        return 0
    if k==0 or k==n:
        return 1
    return (A[n]*B[k]*B[n-k])%MOD
ans = 0
for i in range(N,M+1):
    ans = (ans+comb(i,N))%MOD
print(ans)