#include 
#include 
#include 
#include 
#include 

using namespace std;
int m;  int n;
bool visited[300005];
stacks;
vectorgraph[300005];
vectorrev_graph[300005];
void dfs(int node){
visited[node]=true;
for(int i=0; i> n >> m;
        for(int i=0; i>a>>b;
            a--;
            b--;
            
        graph[b].push_back(a);
        rev_graph[a].push_back(b);
    }
    memset(visited,  false, sizeof visited);

    for(int i=0; i