#include<bits/stdc++.h>
#define ll long long
#define pb push_back
#define mkp make_pair
#define vi vector<int>
#define pii pair<int,int>
#define FI(n) FastIO::read(n)
#define FO(n) FastIO::write(n)
#define ull unsigned long long
#define mst(a,b) memset(a,b,sizeof(a))
#define foR(i,k,j) for(int i=(k);i>=(j);i--)
#define For(i,k,j) for(int i=(k);i<=(j);i++)
#define Foe(i,u) for(int i=lst[u],v=e[i].v;i;i=e[i].nxt,v=e[i].v)
#define IOS ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define Fin(s) freopen(s,"r",stdin)
#define Fout(s) freopen(s,"w",stdout)
#define file(s) Fin(s".in"),Fout(s".out")
#define INF ((1ll<<60)-1)
#define int long long
const int P=998244353; //
using namespace std;
template<typename T>inline void ckmax(T &a,T b) {(a<b)&&(a=b);}
template<typename T>inline void ckmin(T &a,T b) {(a>b)&&(a=b);}
inline int mul(int a,int b) {return 1ull*a*b%P;}
inline int add(int a,int b) {return a+b>=P?a+b-P:a+b;}
inline int sub(int a,int b) {return a-b>=0?a-b:a-b+P;}
inline void mulmod(int &a,int b) {a=mul(a, b);}
inline void addmod(int &a,int b) {((a+=b)>=P)&&(a-=P);}
inline void submod(int &a,int b) {((a-=b)<0)&&(a+=P);}
inline int ksm(int a,int b) {int ans=1; for(;b;b>>=1) {if(b&1) ans=1ll*ans*a%P;a=1ll*a*a%P;}return ans;}
inline void fprint(const int &x,char c=' ') {fprintf(stderr,"%d%c",x,c);}
inline void fprint(const pii &x,char c='\n') {fprintf(stderr,"%d %d%c",x.first,x.second,c);}
inline void fprint(const int *f,const int &n,char c='\n') {for(int i=1;i<=n;i++) fprint(f[i]); fprintf(stderr,"%c",c);}
inline void fprint(const vector<int> &f,char c='\n') {for(int i=0;i<(int)f.size();i++) fprint(f[i]); fprintf(stderr,"%c",c);}
inline int inv(int a) {return ksm(a,P-2);}
namespace FastIO {
  const int SIZE=1<<16; char buf[SIZE],obuf[SIZE],str[64]; int bi=SIZE,bn=SIZE,opt;
  int read(char *s) {
    while (bn) {for (;bi<bn&&buf[bi]<=' ';bi++);if (bi<bn) break; bn=fread(buf,1,SIZE,stdin),bi=0;}
    int sn=0;while (bn) {for (;bi<bn&&buf[bi]>' ';bi++) s[sn++]=buf[bi];if (bi<bn) break; bn=fread(buf,1,SIZE,stdin),bi=0;}s[sn]=0;return sn;
  }
  bool read(int& x) {if(x)x=0;int bf=0,n=read(str); if(!n) return 0; int i=0; if (str[i]=='-') bf=1,i=1; for(x=0;i<n;i++) x=x*10+str[i]-'0'; if(bf) x=-x; return 1;}
  void write(int x) {
    if(!x) obuf[opt++]='0'; else {if(x<0) obuf[opt++]='-',x=-x;int sn=0; while(x)str[sn++]=x%10+'0',x/=10;for (int i=sn-1;i>=0;i--) obuf[opt++]=str[i];}
    if (opt>=(SIZE>>1)){fwrite(obuf,1,opt,stdout); opt=0;}
  }
  void write(char x) {obuf[opt++]=x;if (opt>=(SIZE>>1)){fwrite(obuf,1,opt,stdout); opt=0;}}
	void Fflush() {if (opt) fwrite(obuf,1,opt,stdout); opt=0;}
};
inline int read() {int x; FI(x); return x;}
const int MN=5e3+5;
int n,m,a[MN],pw[MN][MN]; 
signed main() {
	#ifndef ONLINE_JUDGE
		freopen("pro.in","r",stdin);
		freopen("pro.out","w",stdout);
	#endif
	n=read(),m=read();
	For(i,0,MN-5) {
		pw[i][0]=1;
		For(j,1,MN-5) pw[i][j]=mul(pw[i][j-1],i);
	}
	int ans=mul(ksm(m,n),n);
	For(i,2,n) { // len
		For(j,1,m) { // now				
			submod(ans,mul(n-i+1,mul(pw[j-1][i-2],pw[m][n-i])));
		}
	}
	cout<<ans<<endl;
	return FastIO::Fflush(),0; 
}
/*

*/

#include <bits/stdc++.h>
#define i64 long long
#define sz(a) int ((a).size())
#define rep(i, a, b) for (int i = (a); i < (b); ++i)
#define per(i, a, b) for (int i = (b) - 1; i >= (a); --i)
using namespace std;

const int M = 998244353;

struct mint {
	int x;
	mint (int x = 0) : x(x) {}
	friend mint operator +
	(const mint a, const mint &b) {
		int x = a.x + b.x;
		return mint (x >= M ? x - M : x);
	}
	friend mint operator - 
	(const mint a, const mint &b) {
		int x = a.x - b.x;
		return mint (x < 0 ? x + M : x);
	}
	friend mint operator *
	(const mint a, const mint &b) {
		return mint (1ll * a.x * b.x % M);
	}
};

int Pw(int a, int x = M - 2, int res = 1) {
	for (; x; x >>= 1, a = (mint (a) * a).x)
		if (x & 1) res = (mint (res) * a).x;
	return res;
}

const int N = 5000;
int n, m, pw[N];

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> m;
	pw[0] = 1;
	rep(i, 1, n) {
		pw[i] = (mint (pw[i - 1]) * m).x;
	}
	int res = (mint (n) * Pw(m, n)).x;
	rep(x, 0, m) {
		int px = 1;
		rep(y, 0, n - 1) {
			res = (res - mint (n - 1 - y) * px * pw[n - 2 - y]).x;
			px = (mint (px) * x).x;
		}
	}
	cout << res << '\n';
	return 0;
}

/*
	* Read Carefully! Multiple cases? Data range?
	* Transformation? Special cases? Brute & Regularities?
	* Don't get stuck! New directions! Record thoughts!
	* Int overflow? Array bounds? N = 1?
*/