POJ2502
描述：
You have just moved from a quiet Waterloo neighbourhood to a big, noisy city.
你刚刚搬家到一个大城市。
Instead of getting to ride your bike to school every day, you now get to walk and take the subway. 
你只能步行或乘坐地铁上学。
Because you don't want to be late for class, you want to know how long it will take you to get to school.
为了避免迟到，你想知道到学校需要多长时间。
You walk at a speed of 10 km/h. The subway travels at 40 km/h.
步行速度10km/h，地铁速度40km/h。
Assume that you are lucky, and whenever you arrive at a subway station, a train is there that you can board immediately.
假设你很幸运，每当你到地铁站时，你总能立即乘坐地铁。
You may get on and off the subway any number of times, and you may switch between different subway lines if you wish.
你可以乘坐地铁任意多次，你可以随意换乘地铁。
All subway lines go in both directions.
地铁线路都是双向的。

输入：
Input consists of the x,y coordinates of your home and your school, followed by specifications of several subway lines.
输入包括你家和学校的坐标（x，y），接下来是一些地铁线路的详细信息。
Each subway line consists of the non-negative integer x,y coordinates of each stop on the line, in order.
每条地铁线路包括一个有序的非负坐标（x，y）序列，表明了这条线路上的每个车站。
You may assume the subway runs in a straight line between adjacent stops, and the coordinates represent an integral number of metres.
假定地铁在相邻的两站之间总是走直线，这些坐标代表了一个 整数米的长度。
 Each line has at least two stops.
每条线路至少有两站。
The end of each subway line is followed by the dummy coordinate pair -1,-1.
每条线路以一个坐标对（－1，－1）结束。
In total there are at most 200 subway stops in the city.
这座城市中至多只有200个地铁站。

输出：
Output is the number of minutes it will take you to get to school, rounded to the nearest minute, taking the fastest route.
输出从家到学校的最少时间（分钟，四舍五入）。