#include <bits/stdc++.h>
using namespace std;
const int maxn = 1010;
int n, m, d[maxn], pre[maxn];
vector<int> path, ans, G[maxn];
int main() {
scanf("%d %d", &n, &m);
if (m >= n) puts("NO"), exit(0);
if (n == 1) puts("YES\n1\n1"), exit(0);
if (n == 2) puts("YES\n2\n1 1"), exit(0);
while (m--) {
int u, v;
scanf("%d %d", &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 (int i : path) d[i] = 0;
bfs();
if (*max_element(d + 1, d + n + 1) > 2) puts("NO"), exit(0);
for (int i = 1; i + 1 < path.size(); i++) {
for (int 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]);
}
printf("YES\n%d\n", 2 * ans.size());
for (int x : ans) printf("%d ", x);
reverse(ans.begin(), ans.end());
for (int x : ans) printf("%d ", x);
return 0;
}
