import sys read = sys.stdin.buffer.read readline = sys.stdin.buffer.readline readlines = sys.stdin.buffer.readlines import numpy as np MOD = 10 ** 9 + 7 def cumprod(A, MOD=MOD): L = len(A) Lsq = int(L**.5 + 1) A = np.resize(A, Lsq**2).reshape(Lsq, Lsq) for n in range(1, Lsq): A[:, n] *= A[:, n - 1] A[:, n] %= MOD for n in range(1, Lsq): A[n] *= A[n - 1, -1] A[n] %= MOD return A.ravel()[:L] def make_fact(U, MOD=MOD): x = np.arange(U, dtype=np.int64) x[0] = 1 fact = cumprod(x, MOD) x = np.arange(U, 0, -1, dtype=np.int64) x[0] = pow(int(fact[-1]), MOD - 2, MOD) fact_inv = cumprod(x, MOD)[::-1] fact.flags.writeable = False fact_inv.flags.writeable = False return fact, fact_inv fact, fact_inv = make_fact(10 ** 5 + 10) N, M = map(int, read().split()) def power(A, n): if n == 1: return A B = power(A, n // 2) B = B * B % MOD return A * B % MOD if n & 1 else B comb = fact[M] * fact_inv[: M + 1] % MOD * fact_inv[: M + 1][::-1] % MOD power = power(np.arange(M + 1, dtype=np.int64)[::-1], N) x = comb * power % MOD x[1::2] *= (-1) print(x.sum() % MOD)