#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

#define rd(v) long v=0;{long _c;while(_c=*rp++-48,_c>=0)v=v*10+_c;}
#define rd_long() ({ rd(v); v; })
#define wt(v) {ulong _z=v;do*--wp=_z%10+48;while(_z/=10);}
#define rep4(v,s,e,t) for(long v=s;v<e;v+=t)

typedef unsigned long ulong;

#define MD 998244353

#define M 200001
int fac[M],ifac[M];

int inverse(int a){
	int b=MD;
	int u=1;
	int v=0;
	int s,t;
	while(b){
		t=a/b;
		s=b; b=a-t*b; a=s;
		s=v; v=u-t*v; u=s;
	}
	if(u<0){
		u+=MD;
	}
	return u;
}

void mkfac(){
	long x=1;
	fac[0]=x;
	for(long i=1;i<M;i++){
		x=x*i%MD;
		fac[i]=x;
	}
	x=inverse(x);
	for(long i=M;i--;){
		ifac[i]=x;
		x=x*i%MD;
	}
}

int main(){
	long n,k;
	{
		char rbuf[64];
		read(0,rbuf,sizeof rbuf);
		char*rp=rbuf;
		n=rd_long();
		k=rd_long();
	}
	long z;
	if(k==0||k==n){
		z=1;
	}else if(k==1){
		z=n&1?n-2:2;
	}else{
		mkfac();
		z=0;
		rep4(i,0,n-k+1,2){
			z+=(long)fac[n-2-i]*ifac[n-k-i]%MD*(i+1)%MD;
		}
		z=z%MD*ifac[k-2]%MD;
	}
	{
		char wbuf[64],*wp=wbuf+sizeof wbuf;
		wt(z);
		write(1,wp,wbuf+sizeof wbuf-wp);
	}
	_exit(0);
}