class Combination: """階乗とその逆元のテーブルをO(N)で事前作成し、組み合わせの計算をO(1)で行う""" def __init__(self, n, MOD): self.fact = [1] for i in range(1, n + 1): self.fact.append(self.fact[-1] * i % MOD) self.inv_fact = [0] * (n + 1) self.inv_fact[n] = pow(self.fact[n], MOD - 2, MOD) for i in reversed(range(n)): self.inv_fact[i] = self.inv_fact[i + 1] * (i + 1) % MOD self.MOD = MOD def inverse(self, k): """kの逆元を求める O(1)""" return (self.inv_fact[k] * self.fact[k - 1]) % self.MOD def factorial(self, k): """k!を求める O(1)""" return self.fact[k] def inverse_factorial(self, k): """k!の逆元を求める O(1)""" return self.inv_fact[k] def permutation(self, k, r): """kPrを求める O(1)""" if k < r: return 0 return (self.fact[k] * self.inv_fact[k - r]) % self.MOD def combination(self, k, r): """kCrを求める O(1)""" if k < r: return 0 return (self.fact[k] * self.inv_fact[k - r] * self.inv_fact[r]) % self.MOD def combination2(self, k, r): """kCrを求める O(r) kが大きいが、r <= nを満たしているときに使用 """ if k < r: return 0 res = 1 for l in range(r): res *= (k - l) res %= self.MOD return (res * self.inv_fact[r]) % self.MOD n, k = map(int, input().split()) MOD = 998244353 comb = Combination(10 ** 6, MOD) ball = n ans = 0 ans = [0] * (k + 1) for box in range(1, k + 1): ans[box] = pow(box, ball, MOD) for i in range(box): ans[box] -= ans[i] * comb.combination(box, i) ans[box] %= MOD for box in range(1, k + 1): ans[box] *= comb.combination(k, box) ans[box] %= MOD res = 0 for i in range(k + 1): if (k - i) % 2 == 1: res += ans[i] print(res % MOD)