# #4997. [Usaco2017 Feb]Why Did the Cow Cross the Road III

#### 题目描述

Why did the cow cross the road? Well, one reason is that Farmer John's farm simply has a lot of road

s, making it impossible for his cows to travel around without crossing many of them.

FJ's farm is arranged as an N×N square grid of fields (2 <= N <= 100), Certain pairs of adjacent fi
elds (e.g., north-south or east-west) are separated by roads, and a tall fence runs around the exter
nal perimeter of the entire grid, preventing cows from leaving the farm. Cows can move freely from a
ny field to any other adjacent field (north, east, south, or west), although they prefer not to cros
FJ的农场在N×N的网格中（2≤N≤100），某些相邻的区域（例如，南北或东西）由道路分隔，高大的围栏围绕着

There are K cows (1 <= K <= 100, K <= N^2) on FJ's farm, each located in a different field. A pair o
f cows is said to be "distant" if, in order for one cow to visit the other, it is necessary to cross

#### 输入格式

The first line of input contains N, K, and R.

The next R lines describe R roads that exist between pairs of adjacent fields.
Each line is of the form r c c r' c'(integers in the range 1…N)
indicating a road between the field in (row r, column c) and the adjacent field in (row r',column c').
The final K lines indicate the locations of the K cows, each specified in terms of a row and column.

#### 输出格式

Print the number of pairs of cows that are distant.

#### 样例输入

``````
3 3 3
2 2 2 3
3 3 3 2
3 3 2 3
3 3
2 2
2 3``````

#### 样例输出

``````
2``````