#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
using namespace std;

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

const int maxn = 1e5 + 5;
vector <int> G[maxn], Comp[maxn];
stack < pair <int,int> > Stk;
int Low[maxn], Lev[maxn], ans;

void Get_comp (int x, int y) {
    int a, b;
    ans++;
    do {
        a = Stk.top().first;
        b = Stk.top().second;
        Stk.pop();
        Comp[ans].push_back(b);
    } while (a != x || b != y);
    Comp[ans].push_back(a);
}

void Dfs (int node) {
    vector <int> :: iterator it;
    Low[node] = Lev[node];
    for (it = G[node].begin(); it != G[node].end(); it++) {
        if (Lev[*it] == 0) {
            Lev[*it] = Lev[node] + 1;
            Stk.push(make_pair(node, *it));
            Dfs(*it);
            Low[node] = min(Low[node], Low[*it]);
            if (Low[*it] >= Lev[node]) Get_comp(node, *it); /// node = punct de articulatie
        } else {
            Low[node] = min(Low[node], Lev[*it]);
        }
    }
}

int main() {
    ios_base :: sync_with_stdio (false);
    int n, m, i, j, x, y;
    fin >> n >> m;
    for (i = 1; i <= m; i++) {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    Lev[1] = 1;
    Dfs(1);
    fout << ans << "\n";
    for (i = 1; i <= ans; i++) {
        for (j = 0; j < (int) Comp[i].size(); j++) {
            fout << Comp[i][j] << " ";
        }
        fout << "\n";
    }
    fin.close();
    fout.close();
    return 0;
}