#include <bits/stdc++.h>

using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

int n, m, x, y;
const int NMAX = 100001;
vector<int> a[NMAX];
int dfscnt, dfsnr[NMAX], low[NMAX];

using pii = pair<int, int>;
stack<pii> s;
vector<vector<int>> comp;

void print(int x, int tx) {
    vector<int> v;
    pii p;
    do {
        p = s.top();
        s.pop();
        v.push_back(p.first);
        v.push_back(p.second);
    } while (p != make_pair(x, tx));
    comp.push_back(v);
}

void biconex(int x, int tx) {
    dfsnr[x] = ++dfscnt;
    low[x] = dfscnt;

    for (int p : a[x]) {
        if (p == tx) {
            continue;
        }

        if (dfsnr[p] == -1) {
            s.push(make_pair(p, x));
            biconex(p, x);
            low[x] = min(low[x], low[p]);
            if (low[p] >= dfsnr[x]) {
                print(p, x);
            }
        } else {
            low[x] = min(low[x], dfsnr[p]);
        }
    }
}

int main() {
    fin >> n >> m;
    for (int i = 0; i < m; i++) {
        fin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for (int i = 1; i <= n; i++) {
        dfsnr[i] = -1;
        low[i] = -1;
    }
    biconex(1, -1);

    fout << comp.size() << "\n";
    for (auto& v : comp) {
        sort(v.begin(), v.end());
        v.erase(unique(v.begin(), v.end()), v.end());
        for (auto x : v) {
            fout << x << " ";
        }
        fout << "\n";
    }
}