#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define int long long
#define pb push_back
void dbg_out() { cerr << endl; }
template<typename H, typename... T>
void dbg_out(H h, T... t) { cerr << ' ' << h; dbg_out(t...); }
#define dbg(...) {cerr << #__VA_ARGS__ << ':'; dbg_out(__VA_ARGS__); }

void solve(){
	int n, m; cin >> n >> m;
	vector<set<pair<int, int>>> ge(n);
	vector<set<pair<int, int>>> gs(n);
	for(int i = 0, a, b; i< m; i++){
		cin >> a >> b;
		a--, b--;
		ge[b].insert({a, i});
		gs[a].insert({b, i});
	}
	vector<int> s(n), e(n);
	for(int i = 0; i < n; i++){
		s[i] = gs[i].size();
		e[i] = ge[i].size();
	}
	set<pair<int, int>> pq;
	for(int i = 0; i < n; i++){
		pq.insert({s[i] - e[i], i});
	}
	vector<int> re;
	while(!pq.empty()){
		auto at = *(pq.rbegin());
		pq.erase(at);
		for(auto i : gs[at.second]){ // i.first o nó da saida e i.second o indice da aresta
			re.push_back(i.second); //dependencia que sera aceita
			if(pq.count({s[i.first] - e[i.first], i.first}))
				pq.erase({s[i.first] - e[i.first], i.first}); // apago ele da prioty porque ele mudou o grau 
			ge[i.first].erase({at.second, i.second}); // apago no vertice de chegada (atual, indice da aresta)
			e[i.first] = ge[i.first].size(); // atualizo a quantidade de entrada dele 
			//cout << i.first + 1 << " no saida " << ge[i.first].size() << " " << gs[i.first].size() << "\n";
			pq.insert({s[i.first] - e[i.first], i.first});
		}
		for(auto i : ge[at.second]){ // i.first o nó da saida e i.second o indice da aresta
			if(pq.count({s[i.first] - e[i.first], i.first}))
				pq.erase({s[i.first] - e[i.first], i.first}); // apago ele da prioty porque ele mudou o grau 
			gs[i.first].erase({at.second, i.second}); // apago no vertice de chegada (atual, indice da aresta)
			s[i.first] = gs[i.first].size(); // atualizo a quantidade de saida dele 
			//cout << i.first + 1 << " no entrada " << ge[i.first].size() << " " << gs[i.first].size() << "\n";
			pq.insert({s[i.first] - e[i.first], i.first});
		}
	}
	sort(re.begin(), re.end());
	cout << "YES\n";
	cout << re.size() << "\n";
	for(auto i : re)
		cout << i + 1 << " ";
	cout << "\n";
}

signed main(){
	ios::sync_with_stdio(false); cin.tie(0);
	solve();
}