#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

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

using namespace std;
using namespace atcoder;
using mint = modint998244353;
int mod = 998244353;
mint f[2010][2010],fa[2010],fi[2010];
mint pw(mint a,int x){
    mint ret = 1;
    while(x){
        if(x&1) (ret *= a);
        (a *= a); x /= 2;
    }
    return ret;
}

mint nck(int n,int k){
    if(n<0 || k<0 || n<k) return 0;
    return fa[n]*fi[k]*fi[n - k];
}

void solve(){
    int MX = 2010;
    fi[0] = fa[0] = 1;
    for(int i=1;i<MX;i++) fa[i] = fa[i - 1]*i;
    fi[MX - 1] = (mint)1/fa[MX - 1];
    for(int i=MX - 2;i>=1;i--) fi[i] = fi[i + 1]*(i + 1);
}

int main(){
    int i,j,k,x,n,m; cin >> n >> m;
    solve();
    for(k=0;k<=n;k++){
        vector<mint> g(n + 2),h(n + 2);
        for(j=0;j<=n + 1;j++) g[j] = pw(m + 1 - j,k)*pw(mod - 1,j)*fi[j];
        for(j=0;j<=n + 1;j++) h[j] = fi[j];
        g = convolution(g,h);
        for(j=0;j<=min(m + 1,n + 1);j++) f[k][j] = pw(m + 1,n - k)*fa[j]*g[j];
    }
    mint ans = 0;
    for(i=1;i<=n + 1;i++){
        for(k=1;k<=n;k++) ans += nck(n,k)*f[k][i];
    }
    cout << ans.val() << endl;
}