// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
#define pb push_back
#define sz(x) int(x.size())
template<class T> using V = vector<T>;
using vi = V<int>;
const int INF = 1e9 + 10;
int main() {
cin.tie(0)->sync_with_stdio(0);
int N, M; cin >> N >> M;
V<vi> adj(N);
for(int i = 0; i < M; i++) {
int u, v; cin >> u >> v; --u, --v;
adj[u].pb(v);
adj[v].pb(u);
}
if (M != N - 1) {
cout << "NO" << nl;
exit(0-0);
}
if (N == 1) {
cout << "YES" << nl;
cout << 1 << nl;
cout << 1 << nl;
exit(0-0);
}
if (N == 2) {
cout << "YES" << nl;
cout << 2 << nl;
cout << 1 << " " << 1 << nl;
exit(0-0);
}
vi D(N, -1), par(N);
auto bfs = [&]() {
vi q; for(int i = 0; i < N; i++) if (D[i] == 0) q.pb(i);
for(int i = 0; i < sz(q); i++) {
int u = q[i];
for(auto& v : adj[u]) if (D[v] == -1) {
D[v] = D[u] + 1; par[v] = u;
q.pb(v);
}
}
};
D = vi(N, -1); D[0] = 0; bfs();
int s = max_element(begin(D), end(D)) - begin(D);
D = vi(N, -1); D[s] = 0; bfs();
int t = max_element(begin(D), end(D)) - begin(D);
D = vi(N, -1); D[t] = 0; bfs();
vi path;
for(int u = par[s]; u != t; u = par[u]) path.pb(u);
D = vi(N, -1); for(auto& u : path) D[u] = 0;
bfs();
if (*max_element(begin(D), end(D)) > 2) {
cout << "NO" << nl;
exit(0-0);
}
vi ans;
for(int i = 0; i < sz(path); i++) {
int u = path[i];
ans.pb(u);
for(auto& v : adj[u]) if (D[v] && sz(adj[v]) > 1) {
ans.pb(v); ans.pb(u);
}
}
cout << "YES" << nl;
cout << 2 * sz(ans) << nl;
for(auto& x : ans) cout << x + 1 << " ";
reverse(begin(ans), end(ans));
for(auto& x : ans) cout << x + 1 << " ";
cout << nl;
exit(0-0);
}
