#include <bits/stdc++.h>

using namespace std;

#define MAX 100005

bool detectCycle(int nodes, vector<vector<int> >& adjList)
{
    if(nodes==1) return false;
    stack<int> st;
    bool on_stack[MAX+1]= {0};
    bool visited[MAX+1]= {0};
    for(int i=0; i<nodes; i++) //In case the graph is disconnected
    {
        if(visited[i]) continue; //For time efficiency
        st.push(i);
        while(!st.empty())
        {
            int u=st.top();
            if(!visited[u])
            {
                visited[u]=1;
                on_stack[u]=1;
            }
            else //backtracking, but keeping the visited array unchanged for time efficiency
            {
                on_stack[u]=0;
                st.pop();
                continue;
            }
            for(int j=0; j<adjList[u].size(); j++)
            {
                int v=adjList[u][j];
                if(!visited[v])
                {
                    st.push(v);
                }
                else
                {
                    if(on_stack[v]) return true; //cycle detected
                }
            }
        }
    }
    return false;
}


int main()
{
    vector<vector<int> > adjList(MAX+1);
    int nodes, edges;
    cout<<"Enter the number of nodes: ";
    cin>>nodes;
    cout<<endl;
    cout<<"Enter the number of edges: ";
    cin>>edges;
    cout<<endl;
    cout<<"Enter the pair of edges: "<<endl;
    for(int i=0; i<edges; i++)
    {
        int from, to;
        cin>> from>> to;
        adjList[from].push_back(to);
    }
    if(detectCycle(nodes, adjList)==1) cout<<"Cycle found!"<<endl;
    else cout<<"Cycle not found!"<<endl;
    return 0;
}