def prime(n):
    if n < 2:
        return False
    for i in range(2, int(n/2) + 1):
        if n % i == 0:
            return False
    return True

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

A, B = map(int, input().split())
total_sum = 0
for i in range(A, B + 1):
    if prime(i):
        total_sum += f(i)

print(total_sum)