/*made in mrd*/
#include<bits/stdc++.h>
using namespace std;
const int N=2e5+10;
const int mod=998244353;
#define endl '\n'
#define int long long
#define mem(a,b) memset(a,b,sizeof a)
#define fi first
#define se second
#define lu u<<1
#define ru u<<1|1
#define pb push_back
#define bug1(x) cout<<x<<endl
#define bug2(x,y) cout<<x<<' '<<y<<endl
#define pii pair<int,int>
#define bug3(x,y,z) cout<<x<<' '<<y<<' '<<z<<endl
void init()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
int qsm(int a,int b)
{
    int res=1;
    while(b)
    {
        if(b&1) res=res*a%mod;
        b>>=1;
        a=a*a%mod;
    }
    return res;
}
signed main() {
    init();
    int n,m;
    cin>>n>>m;
    int sum=0;
    for(int i=1;i<=m;i++)
    {
        sum+=(qsm(i,n)-qsm(i-1,n)-qsm(i-1,n-1)*n%mod*(m-i+1)%mod)*i+qsm(i,n-1)*n%mod*(m-i)%mod*i%mod;
        sum%=mod;
    }
    cout<<(sum+mod)%mod<<endl;
    return 0;
}