mod = 998244353
n,m = map(int,input().split())
i = m
S = lambda x:x*(x+1)//2
T = lambda x:x*(x+1)*(2*x+1)//6
ans = 0
while i > 0:
	v = n//i
	j = n//(v+1)
	ans += n*(n+1)*(i-j)-(2+2*n)*v*(S(i)-S(j))+v*(v+1)*(T(i)-T(j))
	i = j
print(ans*pow(2,mod-2,mod)%mod)