l, r = map(int, input().split())
ans = 0
def f(x) :
	return x ** 3 - x ** 2 + x + 1
for i in range(l, r+1) :
	isSosu = True
	for j in range(2, i) :
		isSosu = isSosu and (i % j != 0)
	if isSosu :
		ans += f(i)
print(ans)