#include <bits/stdc++.h>
using namespace std;
#define int long long
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n,M;
cin >> n >> M;
if(M!=n-1){
cout << "NO\n";
return 0;
}
vector<vector<int>> adj(n+1);
for(int i=1;i<=M;i++){
int u,v;cin>>u>>v;
adj[u].emplace_back(v);
adj[v].emplace_back(u);
}
pair<int,int> ans = {0,0};
int p1 = 0;
int p2 = 0;
{
vector<int> subsize(n+1);
function<int(int,int)> subsizeDFS = [&](int x,int p){
subsize[x]=1;
for(int&i:adj[x])if(i!=p)subsize[x]+=subsizeDFS(i,x);
return subsize[x];
};
function<void(int,int,int)> dfs = [&](int x,int p,int dist){
if(ans.first<dist)ans={dist,x};
sort(adj[x].rbegin(),adj[x].rend(),[&](const int &a,const int &b){return subsize[a]<subsize[b];});
for(int&i:adj[x])if(i!=p)dfs(i,x,dist+1);
};
subsizeDFS(1,0);
dfs(1,0,1);
p1 = ans.second;
ans = {0,0};
subsize = vector<int>(n+1);
subsizeDFS(p1,0);
dfs(p1,0,1);
p2 = ans.second;
ans = {0,0};
subsize = vector<int>(n+1);
subsizeDFS(p2,0);
dfs(p2,0,1);
p1 = ans.second;
}
vector<bool> isOnDia(n+1);
{
function<bool(int,int)> dfs = [&](int x,int p){
if(x==p2){isOnDia[x]=true;return true;}
for(int&i:adj[x])if(i!=p)if(dfs(i,x)){isOnDia[x]=true;return true;}
return false;
};
dfs(p1,0);
}
bool works = true;
vector<int> walk;
{
function<void(int,int)> generateDFS = [&](int x,int p){
if(!isOnDia[x]){
if(!isOnDia[p]){
if(adj[x].size()>1)works=false;
return;
}
if(adj[x].size()==2){
walk.emplace_back(x);
walk.emplace_back(p);
} else if(adj[x].size()>2)works=false;
for(int&i:adj[x])if(i!=p)generateDFS(i,x);
return;
}
if(x!=p1 and x!=p2)walk.emplace_back(x);
for(int&i:adj[x])if(!isOnDia[i])generateDFS(i,x);
for(int&i:adj[x])if(i!=p and isOnDia[i])generateDFS(i,x);
};
generateDFS(p1,0);
}
vector<int> revWalk = walk;
reverse(revWalk.begin(),revWalk.end());
for(int&i:revWalk)walk.emplace_back(i);
if(n<=2)walk.emplace_back(1);
if(n==2)walk.emplace_back(1);
if(works){
cout << "YES\n";
cout << walk.size() << '\n';
for(int&i:walk)cout<<i<<' ';
cout << '\n';
} else cout << "NO\n";
}
