#include 
#include 
#include 
//#include 
using namespace std;
int n, m;
vectorgraph[3005];
vectorrev_graph[3005];
bool visited[3005];
stacks;
void dfs(int node){

visited[node]=true;
for(int i=0; i>n>>m;
    for(int i=0; i>a>>b;
        a--;
        b--;
        graph[a].push_back(b);
        rev_graph[b].push_back(a);
    }
    memset(visited, false, sizeof visited);

    for(int i=0; i