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long long输出请使用 %lld服务器的python版本为3.4
Problem L: 畅通工程

Problem L: 畅通工程

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 22  Solved: 3
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Description

Input

Output

Sample Input

1
3 3
1 2
2 3
1 3

Sample Output

4

HINT

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