using System;

using System.Collections.Generic;

public class Graph

{

    int V;

    List<int>[] adj;

    public Graph(int v)

    {

        V = v;

        adj = new List<int>[v];

        for(int i=0; i < V; i++)

        {

            adj[i] = new List<int>();

        }

    }

    public void AddEdge(int src, int dest)

    {

        adj[src].Add(dest);

    }

    public bool isCycleUntill(int i, bool[] visited, bool[] recStack)

    {

        if(recStack[i])

            return true;

        if(visited[i])

            return false;

        visited[i] = true;

        recStack[i] = true;

        var children = adj[i];

        foreach(var child in children)

            if(isCycleUntill(child, visited, recStack))

                return true;

        recStack[i] = false;

        return false;

    }

    public bool isCycle()

    {

        bool[] visited = new bool[V];

        bool[] recStack = new bool[V];

        for(int i=0; i < V; i++)

            if(isCycleUntill(i, visited, recStack))

                return true;

        return false;

    }

}

public class Program

{

    public static void Main()

    {

        Graph g = new Graph(4);

        g.AddEdge(0, 1);

        g.AddEdge(0, 2);

        g.AddEdge(1, 3);

        g.AddEdge(1, 2);

        g.AddEdge(3, 2);

        Console.Write(g.isCycle());

    }

}