#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")

using namespace std;

const int P = 998244353;

int ksm(int x, int y) {
    int res = 1;
    while (y) {
        if (y & 1) res = 1ll * res * x % P;
        x = 1ll * x * x % P;
        y >>= 1;
    }
    return res;
}

signed main() {
    int n, m; scanf("%d%d", &n, &m);
    int res = ksm(m, n);
    for (int i = 1; i < m; ++i) {
        res = (res + 2ll * (ksm(m, n) - ksm(i, n) + P)) % P;
    }
    printf("%d\n", res);
    return 0;
}