#include "bits/stdc++.h"
using namespace std;
#ifdef Nero
#include "Deb.h"
#else
#define deb(...)
#endif
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
for (int i = 0; i < m; ++i) {
int u, v;
cin >> u >> v;
}
cout << "YES" << '\n';
if (n == 1) {
cout << 1 << '\n' << 1 << '\n';
return 0;
}
if (n == 2) {
cout << 2 << '\n' << 2 << ' ' << 2 << '\n';
return 0;
}
cout << (n - 2) * 2 << '\n';
if (n % 2) {
for (int i = 2; i <= n - 1; ++i) {
cout << i << ' ';
}
for (int i = 2; i <= n - 1; ++i) {
cout << i << ' ';
}
} else {
for (int i = 2; i <= n - 1; ++i) {
cout << i << ' ';
}
for (int i = n - 1; i >= 2; --i) {
cout << i << ' ';
}
}
return 0;
}
