#include <iostream>
#include "stdio.h"
#include <vector>
using namespace std;

const int MAXN=100000;
vector <vector <int> > v;
short int was[MAXN];
int k=-1;
bool a=0;
//vector<int> ans;

void dfs(int u){
    was[u]=1;
    //cerr<< u + 1 << "\n";
    for (int j=0; j<(int)v[u].size()&&!a; j++){
        if (was[v[u][j]]==1){
            a=1;
            cout << "YES" << "\n";
            k=v[u][j];
            v.clear();
            v.resize(1);
        }
        else
        {
            //cerr<< u+1<<" -> "<< v[u][j]+1<<"\n";
            dfs(v[u][j]);
        }
    }
    if (a && k!=-1)
    {
        if(u==k) k=-1;
        v[0].push_back(u+1);
    }
    was[u]=2;
}

int main(){
    freopen("cicle.in", "r", stdin);
    freopen("cicle.out", "w", stdout);
    int n, m;
    cin >> n >> m;
    v.resize(n);
    for (int i=0, a, b; i<m; i++){
        cin >> a >> b;
        v[a-1].push_back(b-1);
    }
    for (int i=0; i<n; i++){
        if (was[i]==0){
            dfs(i);
        }
        if (a) break;
    }
    if (!a) { cout << "NO";return 0;}
//  if (ans.size()==0){ cout << "NO"; return 0;}
//  cout << k << " ";
//  cout << ans.size() << " "<< ans[ans.size()-1]<< " ";
    for (int i=v[0].size()-1; i>=0; i--){
        cout << v[0][i] << " ";
    }
    return 0;
}