#include <iostream>
#include <cstdio>
#include <cstring>
#define N 1000005
using namespace std;
typedef long long ll;
const int mod=998244353;
int n,m;
ll fac[N],inv[N];
ll quick_pow(ll a,ll b){
	ll ans=1;
	for(;b;b>>=1,a=a*a%mod)
		if(b&1) ans=ans*a%mod;
	return ans;
}
ll C(int n,int m){
	if(n<m) return 0;
	return fac[n]*inv[m]%mod*inv[n-m]%mod;
}
int main(){
	scanf("%d%d",&n,&m);
	if(m<n) return puts("0"),0;
	fac[0]=inv[0]=1;
	for(int i=1;i<=1000002;i++) fac[i]=fac[i-1]*i%mod;
	inv[1000002]=quick_pow(fac[1000002],mod-2);
	for(int i=1000001;i;i--) inv[i]=inv[i+1]*(i+1)%mod;
	ll ans=0;
	for(int i=1;i<=m;i++) if(i>=m-i&&i>=n-1){
		if(i==m-i){
			ans=(ans+C(m-1,i)-C(m-1,n-2))%mod;
			continue;
		}
		int T=i-n+1;
		ans=(ans+C(m,i)-C(m,i+T))%mod;
	}
	printf("%lld\n",(ans+mod)%mod);
	return 0;
}