大本营里收集点题目放着

1、写一段程序从一纯字母字串中取最长的“对称字符串”，
比如“abcddcacdb”，最长“对称字符串”是“dcacd”
比如“abcdabcdd”，最长“对称字符串”是“dd”
比如“abcdefghijklmn”，无“对称字符串

 

2、字符串排序的问题

给定一组字符串（不含空格），按照字典序(从小到大)排序以后输出。

输入：若干行(少于100)，每行一个字符串（不含空格）,每个字符串最大长度80

输出： 排序以后的结果，每行一个字符串

样例：

输入：                        输出：

Marry                         John

Tom                           Marry

John                          Tom  

 

3、大体意思：一排数字，从中取一个，不能取两边的，用取出的数乘两边的，保留结果，删去该数，继续取，当只剩下最后两边的两个数时，将所有保留的结果相加，问以何种顺序取所得结果最大？

The multiplication puzzle is played with a row of cards, each containing a single positive integer. During the move player takes one card out of the row and scores the number of points equal to the product of the number on the card taken and the numbers on the cards on the left and on the right of it. It is not allowed to take out the first and the last card in the row. After the final move, only two cards are left in the row.

The goal is to take cards in such order as to minimize the total number of scored points.

For example, if cards in the row contain numbers 10 1 50 20 5, player might take a card with 1, then 20 and 50, scoring

10*1*50 + 50*20*5 + 10*50*5 = 500+5000+2500 = 8000

If he would take the cards in the opposite order, i.e. 50, then 20, then 1, the score would be

1*50*20 + 1*20*5 + 10*1*5 = 1000+100+50 = 1150.

Input

The first line of the input contains the number of cards N (3 <= N <= 100). The second line contains N integers in the range from 1 to 100, separated by spaces.

Output

Output must contain a single integer - the minimal score.

Sample Input

6
10 1 50 50 20 5

Sample Output

3650