Problem B. Boring Sum

时间限制 1000 ms   内存限制 128 MB

Number theory is interesting, while this problem is boring.

Here is the problem. Given an integer sequence a 1, a 2, …, a n, let S(i) = {j|1<=j<i, and a j is a multiple of a i}. If S(i) is not empty, let f(i) be the maximum integer in S(i); otherwise, f(i) = i. Now we define bi as a f(i). Similarly, let T(i) = {j|i<j<=n, and a j is a multiple of a i}. If T(i) is not empty, let g(i) be the minimum integer in T(i); otherwise, g(i) = i. Now we define c i as a g(i). The boring sum of this sequence is defined as b 1 * c 1 + b 2 * c 2 + … + b n * c n.

Given an integer sequence, your task is to calculate its boring sum.
 

输入数据

The input contains multiple test cases.

Each case consists of two lines. The first line contains an integer n (1<=n<=100000). The second line contains n integers a 1, a 2, …, a n (1<= a i<=100000).

The input is terminated by n = 0.
 

输出数据

Output the answer in a line.
 

样例输入

复制
5
1 4 2 3 9
0

样例输出

复制
136

样例说明

In the sample, b1=1, c1=4, b2=4, c2=4, b3=4, c3=2, b4=3, c4=9, b5=9, c5=9, so b1 * c1 + b2 * c2 + … + b5 * c5 = 136.
         
 

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