#define MD 998244353
Comb<Mint>c;
ll@n,@m,@k;
if(m==1){
	wt(1<<n);
	exit(0);
}
Matrix<Mint>a(n+1-k,n+1-k),v(n+1-k,1),r;
rep(y,n+1-k){
	rep(x,n+1-k){
		a[y][x]=sum[i,0,y+1](c.C(k+x,k+i)*c.C(n-(k+x),y-i));
	}
	v[y][0]=c.C(n,k+y);
}
a**=m-1;
r=a*v;
wt(sum[i,0,n+1-k](r[0][i]));