task2270

#include <iostream>
#include <vector>

using namespace std;

struct color {
    int a;
    int b;
};

vector <vector<int>> edges;
vector <color> visited;

bool dfs(int v) {
    if (visited[v].a == 1 && visited[v].b != 1) {
        return true;
    }

    if (visited[v].b == 1) {
        return false;
    }

    visited[v].a = 1;
    for (int i = 0; i < edges[v].size(); i++) {
        if (dfs(edges[v][i]))
            return true;
    }

    visited[v].b = 1;
    return false;
}

void dfs1(int v) {
    if (visited[v].b == 1) {
        return;
    }
    visited[v].b = 1;
    cout << v << " ";

    for (int i = 0; i < edges[v].size(); i++) {
        if (visited[edges[v][i]].b != 1) {
            dfs1(edges[v][i]);
            return;
        }
    }


}

int main() {

    int n, m;

    cin >> n >> m;

    visited.resize(n + 1);
    edges.resize(n + 1);
    int a, b;

    for (int i = 1; i <= m; i++) {
        cin >> a >> b;
        edges[a].push_back(b);
    }

    for (int i = 1; i <= n; i++) {
        visited[i].a = 0;
        visited[i].b = 0;
    }


    int ind = -1;

    for (int i = 1; i <= n; i++) {
        if (dfs(i)) {
            ind = i;
            break;
        }
    }

    if (ind == -1)
        cout << "NO";
    else {
        cout << "YES" << endl;
        int check = ind;
        vector<bool> flag(n + 1, false);

        while (!flag[check]) {
            flag[check] = true;
            cout << check << " ";

            for (int i = 0; i < edges[check].size(); i++)
                if (flag[i] == false && visited[edges[check][i]].b != 1) {
                    check = edges[check][i];
                    break;
                }

        }
    }



    return 0;
}