/*
low[node] = cel mai mic nivel pe care putem ajunge din node mergand in jos pe arborele DFS si apoi in sus
pe muchii de intoarcere
*/
#include <iostream>
#include <fstream>
#include <vector>
#include <stack>

using namespace std;

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

const int NMax = 1e5;

vector <int> g[NMax + 5], answer[NMax + 5];
stack <pair <int, int>> st;
int n, m, number;
int level[NMax + 5], low[NMax + 5];
bool use[NMax + 5];

void Read(){
    fin >> n >> m;
    while (m--){
        int x, y;
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
}

void DFS(int node, int father){
    use[node] = 1;
    level[node] = low[node] = level[father] + 1;
    for (auto ngh : g[node]){
        if (use[ngh])
            low[node] = min(low[node], level[ngh]);
        if (ngh == father || use[ngh])
            continue;
        st.push({node, ngh});
        DFS(ngh, node);
        if (low[ngh] >= level[node]){
            number++;
            bool ok = 1;
            while (ok){
                pair <int, int> edge = st.top();
                st.pop();
                int node1 = edge.first, node2 = edge.second;
                if (node1 == node && node2 == ngh)
                    ok = 0;
                answer[number].push_back(node2);
            }
            answer[number].push_back(node);
        }
        low[node] = min(low[node], low[ngh]);
    }
}

void Print(){
    fout << number << '\n';
    for (int i = 1; i <= number; i++){
        for (auto node : answer[i])
            fout << node << ' ';
        fout << '\n';
    }
}

int main(){
    Read();
    DFS(1, 0);
    Print();
    return 0;
}