#include<cstdio>
#include<iostream>
using namespace std;
using ll=long long;
const int Mod=998244353;
ll quickly_power(ll a,int b){
	ll res=1;
	for(;b;b>>=1,(a*=a)%=Mod)if(b&1)(res*=a)%=Mod;
	return res;
}
ll phi(int n){
	ll res=1;
	for(int i=2;i*i<=n;++i)if(n%i==0){
		res*=i-1;
		while(n%i==0)res*=i,n/=i;
		res/=i;
	}
	if(n!=1)res*=n-1;
	return res;
}
int main(){
	int n,k;cin>>n>>k;
	ll ans=1;
	for(int i=1;i<k;++i)
		(ans*=(n-i)*quickly_power(i,Mod-2)%Mod)%=Mod;
	cout<<ans*phi(n)%Mod<<'\n';
	return 0;
}