#include <bits/stdc++.h>

#define X first
#define Y second

using namespace std;

vector<set<int> > gr;
int n, m;
vector<int> p;
vector<int> was;
void find_path(int v, int t){
    vector<int> ans;
    cout << "Cycle:\n";
    while(p[t] != -1){
        ans.push_back(t);
        t = p[t];
    }
    ans.push_back(v);
    reverse(ans.begin(), ans.end());
    for(auto x: ans){
        cout << x << ' ';
    }
    exit(0);

}
int dfs(int t, int start){
    for(int j : gr[t]){
        if(j == start){
            return t;
        }
        if(!was[j]){
            was[j] = 1;
            p[j] = t;
            int k = dfs(j, start);
            if(k != -1) return k;
        }
    }
    return -1;
}
int main() {
    cin >> n >> m;
    gr.resize(n);

    for(int i = 0;i < m;i++){
        int x, y;
        cin >> x >> y;
        gr[x].insert(y);
    }
    p.resize(n);
    was.resize(n);
    for(int i = 0;i < n;i++){
        for(int j = 0;j < n;j++) p[j] = -1;
        for(int j = 0;j < n;j++) was[j] = 0;
        was[i] = 1;
        int to = dfs(i, i);
        if(to != -1) find_path(i, to);
    }
    cout << "No cycles";
    return 0;
}