#include <iostream>

#include <atcoder/modint>
#include <atcoder/convolution>

using mint = atcoder::modint998244353;

std::vector<mint> inv(const std::vector<mint> &f) {
    const int n = f.size();
    std::vector<mint> res { f[0].inv() };
    for (int k = 1; k < n; k *= 2) {
        const int l = std::min(2 * k + 1, n);
        std::vector<mint> g(f.begin(), f.begin() + l);
        std::vector<mint> h = atcoder::convolution(res, res);
        h.resize(l);
        g = atcoder::convolution(g, h);
        res.resize(l);
        for (int i = 0; i < l; ++i) res[i] = res[i] + res[i] - g[i];
    }
    return res;
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int n, m;
    std::cin >> n >> m;

    std::vector<mint> f(n + 1);
    // Σ[i=1,m] (1-x^i)^(-1) mod x^(n+1)
    for (int i = 1; i <= m; ++i) for (int j = 0; i * j <= n; ++j) {
        ++f[i * j];
    }
    // f *= 1 - x
    for (int i = n - 1; i >= 0; --i) {
        f[i + 1] -= f[i];
    }
    f[0] += 1 - m;
    
    std::cout << (mint(m).pow(n) - inv(f)[n]).val() << std::endl;
    return 0;
}