CF687E.TOF

普及/提高-

通过率:0%

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题目描述

The first line of the input contains two integers nn and mm ( 1<=n,m<=50001<=n,m<=5000 ) — the number of vertices and then number of directed edges in the input graph.

Each of the next mm lines contains a pair of integers uiu_{i} and viv_{i} ( 1<=ui,vi<=n1<=u_{i},v_{i}<=n ), meaning there is a directed edge in the input graph.

You may assume that the graph won't contain any self-loops and there is at most one edge between any unordered pair of vertices.

输入格式

Print a single integer — the minimum possible number of dfs calls that can be achieved with permuting the edges.

输出格式

输入输出样例

  • 输入#1

    3 3
    1 2
    2 3
    3 1
    

    输出#1

    2998
    
  • 输入#2

    6 7
    1 2
    2 3
    3 1
    3 4
    4 5
    5 6
    6 4
    

    输出#2

    3001
    
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