#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin("sortaret.in");
ofstream fout("sortaret.out");
const int N=50000;
int n,m;
vector<int>v[N+5];
int in[N+5];
queue<int>q;
int stiva[N+5],vf;
int main(){
    fin>>n>>m;
    for(int i=1;i<=m;i++){
        int a,b;
        fin>>a>>b;
        ///cout<<a<<" "<<b<<"\n";
        v[a].push_back(b);
        in[b]++;
    }
    ///return 0;
    for(int i=1;i<=n;i++)
        if(in[i]==0)
            q.push(i);
    while(!q.empty()){
        int nod=q.front();
        q.pop();
        stiva[++vf]=nod;
        for(int i=0;i<v[nod].size();i++){
            int nod_nou=v[nod][i];
            in[nod_nou]--;
            if(in[nod_nou]==0)
                q.push(nod_nou);
        }
    }
    if(vf!=n){
        fout<<"Ciclu!";
    }
    else{
        for(int i=1;i<=vf;i++)
            fout<<stiva[i]<<" ";
    }
    return 0;
}