Time Limit: 1000 mSec Memory Limit : 32768 KB
Problem Description
Year 2900. Many people left Earth and built some cities on Mars.
Currently there are N cities, some of which are connected by narrow one-way roads.
The president of Mars has decided to build police stations throughout the Mars. Given the cost of building police stations at each city, we cannot build them at all cities, due to the financial deficit. The only requirement is that every city must be reachable
from some......
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