#D7766. Number Challenge
Number Challenge
Number Challenge
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).
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).
Examples
Input
2 2 2
Output
20
Input
4 4 4
Output
328
Input
10 10 10
Output
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.
inputFormat
Input
The first line contains three space-separated integers a, b and c (1 ≤ a, b, c ≤ 2000).
outputFormat
Output
Print a single integer — the required sum modulo 1073741824 (230).
Examples
Input
2 2 2
Output
20
Input
4 4 4
Output
328
Input
10 10 10
Output
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.
样例
10 10 10
11536