#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

const int MAX_N = 100000;
const int MAX_M = 1000000;

vector<vector<pair<int, int> > > adj;
vector<bool> visited;
vector<bool> recStack;
vector<bool> takeEdge;

bool dfs(int v) {
    if (!visited[v]) {
        visited[v] = true;
        recStack[v] = true;

        for (const pair<int, int>& neighbor : adj[v]) {
            if (!visited[neighbor.first] && dfs(neighbor.first)) {
                // do nothing
            } else if (recStack[neighbor.first]) {
                takeEdge[neighbor.second] = false;
            }
        }
    }

    recStack[v] = false;
    return false;
}

int main() {
    int n, m;
    cin >> n >> m;

    adj.resize(n);
    visited.assign(n, false);
    recStack.assign(n, false);
    takeEdge.assign(m, true);

    for (int i = 0; i < m; ++i) {
        int a, b;
        cin >> a >> b;
        adj[a - 1].push_back(make_pair(b - 1, i));
    }

    for (int i = 0; i < n; ++i) {
        if (!visited[i]) {
            dfs(i);
        }
    }

    vector<int> ans;
    for (int i = 0; i < m; ++i) {
        if (takeEdge[i]) {
            ans.push_back(i + 1);
        }
    }

    if (2 * ans.size() >= m) {
        cout << "YES" << endl;
        cout << ans.size() << endl;
        for (int e : ans) {
            cout << e << " ";
        }
        cout << endl;
    } else {
        cout << "NO" << endl;
    }

    return 0;
}