def solve(n, k):
    q = [0] * (k + 10)
    mod = 998244353
    ans = 0
    kn = pow(k, n, mod)
    for i in range(k + 1, 0, -1):
        q[i] = kn - pow(i - 1, n, mod) - (k - i + 1) * n * pow(i - 1, n - 1, mod)
        q[i] %= mod
        ans += i * (q[i] - q[i + 1])
        ans %= mod
    return ans

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

print(solve(n, k))