import java.util.*;

public class MaxComponent{
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt(); // вершины
        int m = in.nextInt(); // ребра
        Graph g1 = new Graph(n);
        for (int i = 0; i < m; i++) {
            g1.addEdge(in.nextInt(), in.nextInt());
        }
        g1.findComps();
        System.out.println(g1);
    }

    private static class Graph{
        private int V;
        private Vector<Integer> adj[];
        private boolean[] used;
        private Vector<Integer> comp;
        private Vector<Integer> maxComp;

        public Graph(int v){
            V = v;
            adj = new Vector[V];
            used = new boolean[V];
            comp = new Vector<>();
            maxComp = new Vector<>();
            for (int i = 0; i < v; i++) {
                adj[i] = new Vector<>();
            }
        }

        public void addEdge(int u, int v){
            adj[u].add(v);
            //adj[v].add(u);
        }

        public void findComps(){
            for (int i = 0; i < V; i++) {
                used[i] = false;
            }
            for (int i = 0; i < V; i++) {
                if (!used[i]){
                    comp.removeAllElements();
                    DFS(i);
                    if (comp.size() > maxComp.size()) {
                        maxComp.removeAllElements();
                        maxComp.addAll(comp);
                    }
                }
            }
        }

        public void DFS(int v){
            used[v] = true;
            comp.add(v);
            for (int i = 0; i < adj[v].size(); i++) {
                int to = adj[v].get(i);
                if (!used[to]) DFS(to);
            }
        }

        public String toString(){
            StringBuilder res = new StringBuilder("graph {");
            for (int i = 0; i < V; i++) {
                res.append("\n  ").append(i);
                if (maxComp.contains(i)) res.append(" [color = red]");
            }
            for (int i = 0; i < adj.length; i++) {
                if (!adj[i].isEmpty())
                    for (int j = 0; j < adj[i].size(); j++) {
                        res.append("\n  ").append(i).append(" -- ").append(adj[i].get(j));
                        if (maxComp.contains(i)) res.append(" [color = red]");
                    }
            }
            res.append("\n}");
            return res.toString();
        }
    }
}