def isPrime(n):
    if n <= 1:
        return False
    else:
        i = 2
        while i**2 <= n:
            if n%i == 0:
                return False
            i += 1
        return True

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

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

ans = 0
for n in range(A, B+1):
    if isPrime(n):
        ans += func(n)

print(ans)