#include <iostream>
#include <fstream>
#include <vector>
#define NMAX 100002
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");

struct path {
    int a,b;
} aux;

int n,m,biconex=0,id=1;
int ids[NMAX],low[NMAX];
bool visited[NMAX];
vector <int> g[NMAX],ans[NMAX];
vector <path> Stack;

void dfs(int node) {
    visited[node]=true;
    ids[node]=low[node]=id++;
    for(int i=0; i<g[node].size(); i++) {
        int to=g[node][i];
        if(!visited[to]) {
            aux.a=node;
            aux.b=to;
            Stack.push_back(aux);
            dfs(to);
            low[node]=min(low[node],low[to]);
        }
        if(visited[to]==true && Stack.back().a!=to)
            low[node]=min(low[node],low[to]);

    }
}

int main() {
    fin>>n>>m;
    for(int i=1; i<=m; i++) {
        int x,y;
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }

    for(int i=1; i<=n; i++) {
        if(!visited[i])
            dfs(i);
    }

    for(int i=Stack.size()-1;i>=0;i--) {
        int u=Stack[i].a;
        int v=Stack[i].b;
        if(ids[u]<=low[v]) {
            biconex++;
            while(Stack.back().a!=u && Stack.back().b!=v) {
                ans[biconex].push_back(Stack.back().b);
                Stack.pop_back();
            }
            ans[biconex].push_back(Stack.back().b);
            ans[biconex].push_back(Stack.back().a);
            Stack.pop_back();
        }
    }

    fout<<biconex<<"\n";
    for(int i=1; i<=biconex; i++) {
        while(!ans[i].empty()) {
            fout<<ans[i].back()<<" ";
            ans[i].pop_back();
        }
        fout<<"\n";
    }
    return 0;
}