We define the function f(x) = the number of divisors of x. Given two integers a and b (a ≤ b), please calculate f(a) + f(a+1) + ... + f(b).

Input

Two integers a and b, 1 ≤ a ≤ b ≤ 2³¹ - 1.

Output

The value of f(a) + f(a+1) + ... + f(b).

Sample(s)