Problem I
Instagraph

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every member of the group follows the person,
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the person follows nobody in the group.
The celebrity centrality of person $v$, written $\mathrm{CC}(v)$, is the maximum size of such a group.
We model the social network as a directed graph with $N$ vertices $1$, $\ldots $, $N$. A directed edge from $u$ to $v$ means that person $u$ follows person $v$. For example, in
![\includegraphics[width=0.3\textwidth ]{sample1.png}](/problems/instagraph/file/statement/en/img-0002.png)
we have $\operatorname {CC}(1) = 0$, $\operatorname {CC}(2) = 1$, and $\operatorname {CC}(5) = 2$.
Your task is to find a vertex $v$ with the maximum celebrity centrality $\mathrm{CC}(v)$. In case of a tie, choose the smallest $v$.
Input
The input consists of
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One line with two integers $N$ and $M$ ($1 \le N \le 200\, 000$, $0 \le M \le 1\, 000\, 000$), the number of vertices and the number of directed edges.
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$M$ lines with two distinct integers $u$ and $v$ ($1 \le u,v \le N$), indicating a directed edge from $u$ to $v$. There are no duplicate edges.
Output
Output two integers: the smallest $v$ with the maximum celebrity centrality and the value $\mathrm{CC}(v)$.
Sample Input 1 | Sample Output 1 |
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6 8 1 2 2 1 2 3 3 2 3 6 4 5 5 2 6 5 |
5 2 |
Sample Input 2 | Sample Output 2 |
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1 0 |
1 0 |