typedef __int128_t t;
t f(t i,t n,t v){
	t i2=i*(i+1)/2;
	t i3=i2*(i*2+1)/3;
	t n2=n*(n+1)/2;
	t v2=v*(v+1)/2;
	return i*n2-i2*(n+1)*v+i3*v2;
}
main(){
	t n=0,i=0,a=0,v;
	scanf("%d%d",&n,&i);
	while(i){
		v=n/i;
		a+=f(i,n,v);
		i=n/(v+1);
		a-=f(i,n,v);
	}
	printf("%d",a%998244353);
}