A8692. Number Challenge
编程题
普及/提高-
知识点
题目描述
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 $1073741824$ $(2^{30})$ .
Find the sum modulo $1073741824$ $(2^{30})$ .
输入格式
The first line contains three space-separated integers $a$ , $b$ and $c$ ( $1<=a,b,c<=2000$ ).
输出格式
Print a single integer — the required sum modulo $1073741824$ $(2^{30})$ .
输入输出样例
输入 #1
2 2 2
输出 #1
20
输入 #2
4 4 4
输出 #2
328
输入 #3
10 10 10
输出 #3
11536
说明/提示
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 $1+2+2+3+2+3+3+4=20$ .
- $d(1·1·1)=d(1)=1$ ;
- $d(1·1·2)=d(2)=2$ ;
- $d(1·2·1)=d(2)=2$ ;
- $d(1·2·2)=d(4)=3$ ;
- $d(2·1·1)=d(2)=2$ ;
- $d(2·1·2)=d(4)=3$ ;
- $d(2·2·1)=d(4)=3$ ;
- $d(2·2·2)=d(8)=4$ .
So the result is $1+2+2+3+2+3+3+4=20$ .