n, k = map(int, input().split())
mod = 998244353

fact = [1] * n
inv = [1] * n
finv = [1] * n
for i in range(2, n):
    fact[i] = fact[i - 1] * i % mod
    inv[i] = mod - inv[mod % i] * (mod // i) % mod
    finv[i] = finv[i - 1] * inv[i] % mod
def comb(x, y):
    return fact[x] * finv[y] % mod * finv[x - y] % mod

ans = 0
for i in range(1, n):
    ans += comb(n - 1, i) * pow(i, k, mod) % mod
    ans %= mod
print(ans)