A,B = list(map(int,input().split()))

def prime_factorize(n):
    # https://note.nkmk.me/python-prime-factorization/
    a = []
    while n % 2 == 0:
        a.append(2)
        n //= 2
    f = 3
    while f * f <= n:
        if n % f == 0:
            a.append(f)
            n //= f
        else:
            f += 2
    if n != 1:
        a.append(n)
    return a


def f(n):
    return n**3-n**2+n+1

ans = 0
for i in range(A,B+1):
    if(prime_factorize(i)[0] != i):continue
    ans += f(i)
print(ans)