#include <iostream>
#include <cstdio>
#include <vector>
#include <bitset>
#include <stack>
using namespace std;
 
#define MAX_SIZE 100001
 
int n,m;
vector<int>graf[MAX_SIZE];
bitset<MAX_SIZE>viz;
int nivel[MAX_SIZE],sus[MAX_SIZE];
int nrc;
 
void citire()
{
    scanf("%d %d ",&n,&m);
    for(int i=0;i<m;i++)
    {
        int x,y;
        scanf("%d %d ",&x,&y);
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
}
vector<vector<int>>comp;
stack<int>stiva;
 
void scoate(int nod,int tata)
{
    vector<int>t;
    t.push_back(tata);
    while(stiva.top()!=nod)
    {
        t.push_back(stiva.top());
        stiva.pop();
    }
    t.push_back(nod);
    stiva.pop();
    comp.push_back(t);
}
 
void dfs(int x, int tata)
{
    viz[x]=1;
    nivel[x]=nivel[tata]+1;
    sus[x]=nivel[x];
 
    int nrv = graf[x].size();
 
    for(int i=0; i<nrv; i++)
    {
 
        if(graf[x][i]==tata)
            continue;
 
        if(!viz[graf[x][i]])
        {
            stiva.push(graf[x][i]);
 
            dfs(graf[x][i],x);
 
            sus[x]=min(sus[x],sus[graf[x][i]]);
 
            if(nivel[x]<=sus[graf[x][i]])
            {
                scoate(graf[x][i],x);
                nrc++;
            }
        }
        else
        {
            sus[x]=min(sus[x],nivel[graf[x][i]]);
        }
    }
}
 
int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
 
    citire();
    nivel[0]=-1;
 
    for(int i=1; i<=n; i++)
    {
        stiva.push(i);
        if(!viz[i])
            dfs(i,0);
 
        stiva.pop();
    }
    printf("%d\n",nrc);
    for(int i=0;i<nrc;i++)
    {
        int lg = comp[i].size();
        for(int j=0;j<lg;j++)
            printf("%d ",comp[i][j]);
        printf("\n");
    }
 
    return 0;
}