n, m = map(int, input().split())
d = [0] * (n + 1)
for i in range(1, m + 1):
    for j in range(i, n + 1, i):
        d[j] += i
for i in range(n):
    d[i+1] += d[i]
ans = max(x * m - d[x] for x in range(1, n + 1))
print(ans)