#include <bits/stdc++.h>
using namespace std;
const int N = 1010;
int n, m, d[N], pre[N];
vector<int> path, ans, G[N];
int main()
{
cin >> n >> m;
if (m >= n)
cout << "NO\n", exit(0);
if (n == 1)
cout << "YES\n1\n1", exit(0);
if (n == 2)
cout << "YES\n2\n1 1", exit(0);
while (m --)
{
int u, v;
cin >> u >> v;
G[u].push_back(v), G[v].push_back(u);
}
auto bfs = [&]()
{
queue<int> Q;
for (int i = 1; i <= n; i ++)
if (!d[i])
Q.push(i);
while (!Q.empty())
{
int u = Q.front();
Q.pop();
for (int v : G[u])
if (!~d[v])
Q.push(v), d[v] = d[u] + 1, pre[v] = u;
}
};
memset(d, -1, sizeof(d));
d[1] = 0;
bfs();
int s = max_element(d + 1, d + n + 1) - d;
memset(d, -1, sizeof(d));
d[s] = 0;
bfs();
int t = max_element(d + 1, d + n + 1) - d;
for (int i = t; i ^ s; i = pre[i])
path.push_back(i);
path.push_back(s);
memset(d, -1, sizeof(d));
for (auto i : path)
d[i] = 0;
bfs();
if (*max_element(d + 1, d + n + 1) > 2)
cout << "NO\n", exit(0);
for (int i = 1; i + 1 < path.size(); i++)
{
for (auto j : G[path[i]])
if (d[j] && G[j].size() > 1)
ans.push_back(path[i]), ans.push_back(j);
ans.push_back(path[i]);
}
cout << "YES\n" << 2 * ans.size() << '\n';
for (auto x : ans)
cout << x << " ";
reverse(ans.begin(), ans.end());
for (auto x : ans)
cout << x << " ";
}
