#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;

const int N = 1 << 19;

vector<PII> g[N], gr[N];
int bal[N];
bool used[N];
bool aliveEdge[N];

int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);	
	int n, m;
	cin >> n >> m;
	FOR(i, 0, m)
	{
		int u, v;
		cin >> u >> v;
		u--;
		v--;
		bal[u]--;
		bal[v]++;
		g[u].PB({v, i});
		gr[v].PB({u, i});
		aliveEdge[i] = true;
	}
	set<PII> s;
	FOR(i, 0, n)
		s.insert({bal[i], i});
	VI ans;
	FOR(k, 0, n)
	{
		auto [bj, j] = *s.begin();
		used[j] = true;
		s.erase(s.begin());
		for (auto [to, idx] : g[j])
		{
			if (aliveEdge[idx])
			{
				aliveEdge[idx] = false;
				assert(!used[to]);
				s.erase({bal[to], to});
				bal[to]--;
				s.insert({bal[to], to});
				ans.PB(idx);
			}
		}
		for (auto [from, idx] : gr[j])
		{
			if (aliveEdge[idx])
			{
				aliveEdge[idx] = false;
				assert(!used[from]);
				s.erase({bal[from], from});
				bal[from]++;
				s.insert({bal[from], from});
			}
		}
	}
	cout << "YES\n" << SZ(ans) << "\n";
	for (int i : ans)
		cout << i + 1 << " ";
	cout << "\n";
	return 0;
}