#include<iostream>
#define int long long
#define mod 998244353
int h(int n){
	int ans=0,j=0;
	for(int i=1;i<=n;i=j+1)
	j=(n/((n/i)%mod)%mod)%mod,
	ans=(ans+(n/i)%mod*((j-i+1)%mod)%mod)%mod;
	return ans%mod;
}
signed main(){
	std::ios::sync_with_stdio(0);
	int n,k;
	std::cin>>n>>k;
	std::cout<<(h(k)-h(n-1)+mod)%mod<<"\n";
}