import java.io.*;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.Stack;
import java.util.StringTokenizer;

class FastScanner {
    private BufferedReader br;
    private StringTokenizer st;

    public FastScanner(InputStreamReader reader) {
        br = new BufferedReader(reader);
    }

    public String next() {
        while (st == null || !st.hasMoreTokens()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

    public double nextDouble() {
        return Double.parseDouble(next());
    }

    public void close() throws Exception {
        br.close();
    }
}


public class A {
    public static void main(String[] args) {
        FastScanner s = new FastScanner(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(new BufferedOutputStream(System.out));
        ArrayList<ArrayList<Integer>> sosedi = new ArrayList<>();
        int n = s.nextInt();
        int m = s.nextInt();
        for (int i = 0; i < n; i++) {
            sosedi.add(new ArrayList<>());
        }
        int k1, k2;
        for (int i = 0; i < m; i++) {
            k1 = s.nextInt();
            k2 = s.nextInt();
            sosedi.get(k1 - 1).add(k2 - 1);
        }
        int was[] = new int[n];
        Stack<Integer> road = new Stack<>();

        for (int j = 0; j < n; j++) {
            if (was[j] == 0) {
                road.push(j);
                was[j] = 1;
                while (!road.empty()) {
                    boolean prov = true;
                    for (int i = 0; i < sosedi.get(road.peek()).size(); i++) {
                        if (was[sosedi.get(road.peek()).get(i)] == 0) {
                            road.push(sosedi.get(road.peek()).get(i));
                            was[road.peek()] = 1;
                            prov = false;
                            break;
                        }
                        if (was[sosedi.get(road.peek()).get(i)] == 1) {
                            pw.println("YES");
                            int t = sosedi.get(road.peek()).get(i);
                            String answer = String.valueOf(sosedi.get(road.peek()).get(i) + 1);
                            while (road.peek() != t) {
                                answer = String.valueOf(road.pop() + 1) + " " + answer;
                            }
                            pw.print(answer);
                            pw.close();
                            System.exit(0);
                        }
                    }
                    if (prov) {
                        was[road.pop()] = 2;
                    }
                }
            }

        }

        pw.print("NO");
        pw.close();
    }
}