N, M = map(int, input().split())

import math
def prime(n):
    is_prime = [True] * (n + 1)
    is_prime[0], is_prime[1] = False, False
    for i in range(2, int(math.sqrt(n)) + 1):
        if is_prime[i]:
            for j in range(2 * i, n + 1, i):
                is_prime[j] = False
    return is_prime

prime = prime(N)
for i in range(N + 1)[::-1]:
    if prime[i]:
        xx = i
        break
ans = 0
for i in range(1, M+1):
    ans += xx%i

print(ans)