#include "bits/stdc++.h"
using namespace std;
void solve() {
    int n, m;
    cin >> n >> m;
    vector<vector<int>> g(n);
    vector<vector<int>> ops;
    vector<pair<int, int>> edg(m);
    for (int i = 0; i < m; ++i) {
        int a, b;
        cin >> a >> b;
        a--;b--;
        vector<int> el(n, 1);
        el[a] = 0;
        el[b] = 0;
        vector<int> t;
        for (int j = 0; j < n; ++j) {
            if (el[j])
                t.push_back(j);
        }
        vector<int> t1 = t, t2 = t;
        t1.push_back(a);
        t1.push_back(b);
        t2.push_back(b);
        t2.push_back(a);
        reverse(t2.begin(), t2.end());
        ops.push_back(t1);
        ops.push_back(t2);
    }
    cout << "YES\n";
    cout << ops.size() << '\n';
    for (auto i : ops) {
        for (auto j : i)
            cout << j + 1 << ' ';
        cout << '\n';
    }
}
signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int t = 1;
    //cin >> t;
    while (t--)
        solve();
}