a, b = map(int, input().split())
ans = 0

def is_prime(n):
    if n == 1:
        return False
    for i in range(2, int(n**0.5)+1):
        if n % i == 0:
            return False
    return True


for i in range(a, b+1):
    if is_prime(i):
        ans += i**3 - i**2 + i +1

print(ans)