Codeforces Round 146 (Div. 1)
E
Number Challenge
Codeforces
2600
原题
← D→
翻译中…

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:

翻译中…

image

翻译中…

Find the sum modulo $1073741824$ $(2^{30})$.

翻译中…

Input

翻译中…

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

翻译中…

Output

翻译中…

Print a single integer — the required sum modulo $1073741824$ $(2^{30})$.

翻译中…

Note

翻译中…

For the first example.

翻译中…
  • $*d*(1·1·1) = *d*(1) = 1$;
  • $*d*(1·1·2) = *d*(2) = 2$;
  • $*d*(1·2·1) = *d*(2) = 2$;
  • $*d*(1·2·2) = *d*(4) = 3$;
  • $*d*(2·1·1) = *d*(2) = 2$;
  • $*d*(2·1·2) = *d*(4) = 3$;
  • $*d*(2·2·1) = *d*(4) = 3$;
  • $*d*(2·2·2) = *d*(8) = 4$.
翻译中…

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

翻译中…

样例

Input #1
2 2 2
Output #1
20
InputCopy OutputCopy
Input #2
4 4 4
Output #2
328
InputCopy OutputCopy
Input #3
10 10 10
Output #3
11536
InputCopy OutputCopy
题目信息
题号
235E
时间限制
3 s
内存限制
512 MB
标签
组合数学
动态规划
模拟
数学
数论

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。