#include <bits/stdc++.h>
#pragma GCC optimize(3)
//#define int long long
#define ri register
#define mk make_pair
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define is insert
#define es erase
#define vi vector<int>
#define vpi vector<pair<int,int>>
using namespace std; const int N=3010, Mod=998244353;
inline int read()
{
    int s=0, w=1; ri char ch=getchar();
    while(ch<'0'||ch>'9') { if(ch=='-') w=-1; ch=getchar(); }
    while(ch>='0'&&ch<='9') s=(s<<3)+(s<<1)+(ch^48), ch=getchar();
    return s*w;
}
int n,m,f[N],fac[N+5],inv[N+5],iiv[N+5];
inline int ksc(int x,int p) { int res=1; for(;p;p>>=1, x=1ll*x*x%Mod) if(p&1) res=1ll*res*x%Mod; return res; }
inline int C(int x,int y) { if(x<y||x<0||y<0) return 0; return 1ll*fac[x]*inv[x-y]%Mod*inv[y]%Mod; }
signed main()
{
	fac[0]=1;
	for(ri int i=1;i<=N;i++) fac[i]=1ll*fac[i-1]*i%Mod;
	inv[N]=ksc(fac[N],Mod-2);
	for(ri int i=N;i;i--) inv[i-1]=1ll*inv[i]*i%Mod;
	iiv[1]=1;
	for(ri int i=2;i<=N;i++) iiv[i]=1ll*(Mod-Mod/i)*iiv[Mod%i]%Mod;
	n=read()+1, m=read();
	f[1]=1;
	for(ri int i=2;i<=n;i++)
	{
		f[i]=f[i-1];
		int fir=1,sec=1;
		for(ri int k=0;k<=min(i,m)-2;k++)
		{
			f[i]=(f[i]+1ll*f[i-k-1]*fir%Mod*sec%Mod*C(n-i+k,k)%Mod)%Mod;
			fir=1ll*fir*(m-2-k)%Mod*iiv[k+1]%Mod, sec=1ll*sec*(k+1)%Mod;
		}
	}
	printf("%d\n",f[n]);
	return 0;
}