The Child and Toy

题意翻译

n个带权点,m条无向边,删除一个点就要付出所有与之有联系且没有被删除的点的点权之和的代价。 求删除所有点的最小代价。

题目描述

On Children's Day, the child got a toy from Delayyy as a present. However, the child is so naughty that he can't wait to destroy the toy. The toy consists of $ n $ parts and $ m $ ropes. Each rope links two parts, but every pair of parts is linked by at most one rope. To split the toy, the child must remove all its parts. The child can remove a single part at a time, and each remove consume an energy. Let's define an energy value of part $ i $ as $ v_{i} $ . The child spend $ v_{f1}+v_{f2}+...+v_{fk} $ energy for removing part $ i $ where $ f_{1},f_{2},...,f_{k} $ are the parts that are directly connected to the $ i $ -th and haven't been removed. Help the child to find out, what is the minimum total energy he should spend to remove all $ n $ parts.

输入输出格式

输入格式


The first line contains two integers $ n $ and $ m $ ( $ 1<=n<=1000 $ ; $ 0<=m<=2000 $ ). The second line contains $ n $ integers: $ v_{1},v_{2},...,v_{n} $ ( $ 0<=v_{i}<=10^{5} $ ). Then followed $ m $ lines, each line contains two integers $ x_{i} $ and $ y_{i} $ , representing a rope from part $ x_{i} $ to part $ y_{i} $ ( $ 1<=x_{i},y_{i}<=n; x_{i}≠y_{i} $ ). Consider all the parts are numbered from $ 1 $ to $ n $ .

输出格式


Output the minimum total energy the child should spend to remove all $ n $ parts of the toy.

输入输出样例

输入样例 #1

4 3
10 20 30 40
1 4
1 2
2 3

输出样例 #1

40

输入样例 #2

4 4
100 100 100 100
1 2
2 3
2 4
3 4

输出样例 #2

400

输入样例 #3

7 10
40 10 20 10 20 80 40
1 5
4 7
4 5
5 2
5 7
6 4
1 6
1 3
4 3
1 4

输出样例 #3

160

说明

One of the optimal sequence of actions in the first sample is: - First, remove part $ 3 $ , cost of the action is $ 20 $ . - Then, remove part $ 2 $ , cost of the action is $ 10 $ . - Next, remove part $ 4 $ , cost of the action is $ 10 $ . - At last, remove part $ 1 $ , cost of the action is $ 0 $ . So the total energy the child paid is $ 20+10+10+0=40 $ , which is the minimum. In the second sample, the child will spend $ 400 $ no matter in what order he will remove the parts.