#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> v;
typedef vector<v> vv;
typedef vector<vv> vvv;
typedef pair<ll,ll> p;
typedef vector<p> vp;
typedef vector<vp> vvp;
typedef vector<vvp> vvvp;
typedef pair<ll, p> tri;
typedef vector<tri> vtri;
typedef vector<vtri> vvtri;
typedef vector<vvtri> vvvtri;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
#define f first
#define s second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(),(v).end()
const ll INF = 1e18;
const ll mod = 1e9 + 7;
int main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
ll N, M;
cin >> N >> M;
vv graph(N);
for (ll i= 0; i < M; i++)
{
ll a, b;
cin >> a >> b;
graph[a-1].pb(b-1);
graph[b-1].pb(a-1);
}
cout<<"YES\n";
if (N == 1)
{
cout<<"1\n1\n";
}
else if (N == 2)
{
cout << "2\n1 1\n";
}
else
{
cout << N - 1 << "\n";
for (ll i = 1; i < N - 1; i++) cout << i + 1 << " ";
cout << N - 1 << "\n";
}
return 0;
}
