Pentagon

题意翻译

A megapolis Berbourg有n个路口，m条路，每两个路口之间最多只有一条路。 现在要建一座五角大楼（~~什么鬼~~），要求覆盖5个路口，并且这五个路口能通过道路形成一个环。 你的任务是统计该城市中循环周期为5的不同循环数量。

题目描述

According to the last order issued by the president of Berland every city of the country must have its own Ministry Defense building (their own Pentagon). A megapolis Berbourg was not an exception. This city has $ n $ junctions, some pairs of which are connected by two-way roads. Overall there are $ m $ roads in the city, no more than one between each pair of junctions. At the moment choosing a location place for Pentagon in Berbourg is being discussed. It has been decided that Pentagon should cover the territory of five different junctions which are joined into a cycle by roads. In the order to build Pentagon a special wall will be built along the roads (with high-tension razor, high-voltage wire and other attributes). Thus, the number of possible ways of building Pentagon in the city is equal to the number of different cycles at lengths of 5, composed of junctions and roads. Your task is to prints the number of ways of building Pentagon in Berbourg. Only well-optimized solutions will be accepted. Please, test your code on the maximal testcase.

输入输出格式

输入格式

The first line contains two integers $ n $ and $ m $ ( $ 1<=n<=700;0<=m<=n·(n-1)/2 $ ), where $ n $ represents the number of junctions and $ m $ is the number of roads in the city. Then follow $ m $ lines containing the road descriptions, one in each line. Every road is set by a number of integers $ a_{i},b_{i} $ ( $ 1<=a_{i},b_{i}<=n;a_{i}≠b_{i} $ ), where $ a_{i} $ and $ b_{i} $ represent the numbers of junctions, connected by the road. The junctions are numbered from 1 to $ n $ . It is not guaranteed that from any junction one can get to any other one moving along the roads.

输出格式

Print the single number which represents the required number of ways. Please, do not use %lld specificator to read or write 64-bit integers in C++. It is preffered to use cout (also you may use %I64d).

输入输出样例

输入样例 #1

5 5
1 2
2 3
3 4
4 5
5 1

输出样例 #1

1

输入样例 #2

5 10
1 2
1 3
1 4
1 5
2 3
2 4
2 5
3 4
3 5
4 5

输出样例 #2

12