codeforces#P235E. Number Challenge

    ID: 26168 远端评测题 3000ms 512MiB 尝试: 0 已通过: 0 难度: 10 上传者: 标签>combinatoricsdpimplementationmathnumber theory*2600

Number Challenge

Description

Let's denote d(n) as the number of divisors of a positive integer n. You are given three integers a, b and c. Your task is to calculate the following sum:

Find the sum modulo 1073741824 (230).

The first line contains three space-separated integers a, b and c (1 ≤ a, b, c ≤ 2000).

Print a single integer — the required sum modulo 1073741824 (230).

Input

The first line contains three space-separated integers a, b and c (1 ≤ a, b, c ≤ 2000).

Output

Print a single integer — the required sum modulo 1073741824 (230).

Samples

2 2 2

20

4 4 4

328

10 10 10

11536

Note

For the first example.

  • d(1·1·1) = d(1) = 1;
  • d(1·1·2) = d(2) = 2;
  • d(1·2·1) = d(2) = 2;
  • d(1·2·2) = d(4) = 3;
  • d(2·1·1) = d(2) = 2;
  • d(2·1·2) = d(4) = 3;
  • d(2·2·1) = d(4) = 3;
  • d(2·2·2) = d(8) = 4.

So the result is 1 + 2 + 2 + 3 + 2 + 3 + 3 + 4 = 20.