B"You are given a directed acyclic graph, consisting of n vertices and m edges. The vertices are numbered from 1 to n . There are no multiple edges and self-loops. Let mathit{in}_v be the number of incoming edges (indegree) and mathit{out}_v be the number of outgoing edges (outdegree) of vertex v . You are asked to remove some edges from the graph. Let the new degrees be mathit{in'}_v and mathit{out'}_v . You are only allowed to remove the edges if the following conditions hold for every vertex v : Let's call a set of vertices S cute if for each pair of vertices v and u ( v neq u ) such that v in S and u in S , there exists a path either from v to u or from u to v over the non-removed edges. What is the maximum possible size of a cute set S after you remove some edges from the graph and both indegrees and outdegrees of all vertices either decrease or remain equal to 0 ? The first line contains two integers n and m ( 1 <= n <= 2 cdot 10^5 ; 0 <= m <= 2 cdot 10^5 ) -- the number of vertices and the number of edges of the graph. Each of the next m lines contains two integers v and u ( 1 <= v, u <= n ; v neq u ) -- the description of an edge. The given edges form a valid directed acyclic graph. There are no multiple edges. Print a single integer -- the maximum possible size of a cute set S after you remove some edges from the graph and both indegrees and outdegrees of all vertices either decrease or remain equal to 0 . In the first example, you can remove edges (1, 2) and (2, 3) . mathit{in} = [0, 1, 2] , mathit{out} = [2, 1, 0] . mathit{in'} = [0, 0, 1] , mathit{out'} = [1, 0, 0] . You can see that for all v the conditions hold. The maximum cute set S is formed by vertices 1 and 3 . They are still conn"...