#include <bits/stdc++.h>
using namespace std;
const int N = 1010;
vector<vector<int>> g(N);
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
for (int i = 1; i <= m; i++) {
int x, y;
cin >> x >> y;
g[x].push_back(y);
g[y].push_back(x);
}
if (n - 1 == m) {
cout << "YES\n" << n * 5 << '\n';
vector<int> v(n);
iota(v.begin(), v.end(), 1);
srand(time(0));
for (int rep = 0; rep < 5; rep++) {
random_shuffle(v.begin(), v.end());
random_shuffle(v.begin(), v.end());
random_shuffle(v.begin(), v.end());
for (int i = 0; i < n; i++)
cout << v[i] << ' ';
}
}
return 0;
}
