#include <bits/stdc++.h>
#define sz(x) (int)(x).size()
#define all(x) x.begin(), x.end()
#define For(i, a, b) for(int i = a; i <= b; i++)
#define roF(i, a, b) for(int i = a; i >= b; i--)
using namespace std;
using ll = long long;
using pi = pair<int, int>;
const int N = 1e5 + 5;
const int inf = 0x3f3f3f3f;
// #define int ll
int n, m, par[N];
vector<int> adj[N];
bool ok[N], used[N];
pi dfs(int u, int p = -1){
pi ret(0, u);
for(auto &v : adj[u]){
if(v == p) continue;
par[v] = u;
pi i = dfs(v, u); i.first++;
ret = max(ret, i);
}
return ret;
}
void rmain(){
cin >> n >> m;
if(m != n - 1){ cout << "NO"; return; }
if(n == 1){ cout << "YES\n1\n1"; return; }
if(n == 2){ cout << "YES\n2\n1 1"; return; }
For(i, 1, m){
int u, v; cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
int f = dfs(1).second;
int s = dfs(f).second;
for(int i = s; ; i = par[i]){
ok[i] = 1; used[i] = 1;
for(auto &j : adj[i]){
ok[j] = 1;
for(auto &k : adj[j]) ok[k] = 1;
}
if(i == f) break;
}
if(count(ok + 1, ok + n + 1, 0)){
cout << "NO"; return;
}
vector<int> res;
for(int i = par[s]; i != f; i = par[i]){
res.push_back(i);
for(auto &j : adj[i]){
if(used[i] or sz(adj[j]) == 1)
continue;
res.push_back(j);
res.push_back(i);
}
}
cout << "YES\n" << (sz(res) << 1) << "\n";
for(auto &i : res) cout << i << " ";
reverse(all(res));
for(auto &i : res) cout << i << " ";
}
signed main(int argc, char *argv[]){
iostream::sync_with_stdio(0);
int T = 1;
while(T--) rmain();
return 0;
}
