#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) FOR(i, 0, n)
#define ll long long
using namespace std;
const int MAXN = 1010;
vector <int> ve[MAXN];
int bio[MAXN];
void impossible() {
cout << "NO\n";
exit(0);
}
void dfs(int x, int par) {
bio[x] = bio[par] + 1;
for (int y : ve[x]) {
if (y == par) continue;
if (bio[y]) impossible();
dfs(y, x);
}
return;
}
int main_path[MAXN];
vector <int> path;
int twig[MAXN];
int rek(int x, int par) {
int ma = 0;
for (int y : ve[x]) {
if (y == par) continue;
if (main_path[y]) continue;
ma = max(ma, rek(y, x));
}
if (ma == 3) impossible();
twig[x] = ma;
return ma + 1;
}
vector <int> out;
void print() {
cout << "YES\n";
cout << out.size() << "\n";
for (int x : out) cout << x + 1 << " ";
cout << "\n";
return;
}
int main() {
int n, m;
cin >> n >> m;
if (n == 1) {
out.push_back(0);
print();
return 0;
}
if (n == 2) {
out.push_back(0);
out.push_back(0);
print();
return 0;
}
REP(i, m) {
int a, b;
cin >> a >> b;
a--, b--;
ve[a].push_back(b);
ve[b].push_back(a);
}
dfs(0, 0);
int A = -1, dist = -1;
REP(i, n) {
if (bio[i] > dist) {
dist = bio[i];
A = i;
}
}
memset(bio, 0, sizeof bio);
dfs(A, A);
int B = -1;
dist = -1;
REP(i, n) {
if (bio[i] > dist) {
dist = bio[i];
B = i;
}
}
int x = B;
while (x != A) {
main_path[x] = 1;
path.push_back(x);
for (int y : ve[x]) {
if (bio[y] == bio[x] - 1) {
x = y;
break;
}
}
}
path.push_back(A);
main_path[A] = 1;
memset(twig, 0, sizeof twig);
REP(i, n) {
if (main_path[i]) twig[i] = rek(i, i) - 1;
}
// remove first and last node of path to optimise
if (path.size() > 1) {
main_path[path[0]] = 0;
path.erase(path.begin());
twig[path[0]] = max(twig[path[0]], 1);
}
reverse(path.begin(), path.end());
if (path.size() > 1) {
main_path[path[0]] = 0;
path.erase(path.begin());
twig[path[0]] = max(twig[path[0]], 1);
}
for (int x : path) {
out.push_back(x);
if (twig[x] == 2) {
for (int y : ve[x]) {
if (main_path[y] || twig[y] == 0) continue;
out.push_back(y);
out.push_back(x);
}
}
}
reverse(path.begin(), path.end());
for (int x : path) {
out.push_back(x);
if (twig[x] == 2) {
for (int y : ve[x]) {
if (main_path[y] || twig[y] == 0) continue;
out.push_back(y);
out.push_back(x);
}
}
}
print();
return 0;
}
