#include <bits/stdc++.h>
//#include <windows.h>
#define ED cerr<<endl;
#define TS cerr<<"I AK IOI"<<endl;
#define cr(x) cerr<<x<<endl;
#define cr2(x,y) cerr<<x<<" "<<y<<endl;
#define cr3(x,y,z) cerr<<x<<" "<<y<<" "<<z<<endl;
#define cr4(x,y,z,w) cerr<<x<<" "<<y<<" "<<z<<" "<<w<<endl;
#define pii pair<int,int>
#define mk make_pair
#define fi first
#define se second
//#define int long long
//#define ull unsigned long long
using namespace std;
const int N=1e5+5,INF=2e9,mod=998244353;
int n,m;

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

int main()
{
	scanf("%d%d",&n,&m);
	int qwq=qpow(m,n),ans=qwq;
	for(int i=1;i<=m-1;++i) {
		ans=(ans+2ll*(qwq-qpow(i,n)+mod)+mod)%mod;
	}
	printf("%d\n",ans);
	return 0;
}