#include <fstream>
#include <vector>
#include <stack>
#include <utility>
#define NMAX 100005

using namespace std;

FILE* f=freopen("biconex.in","r",stdin);
FILE* o=freopen("biconex.out","w",stdout);

int n,m;

vector<int> graph[NMAX];
int lvl[NMAX],low[NMAX],par[NMAX];
stack<pair<int,int> > temp;
vector<vector<int> > sol;
int nsol;

void RegisterSol(int x,int y)
{
    sol.push_back(vector<int>());
    while(temp.top()!=make_pair(x,y))
    {
        sol[nsol].push_back(temp.top().second);
        temp.pop();
    }
    sol[nsol].push_back(temp.top().second);
    sol[nsol].push_back(temp.top().first);
    temp.pop();
    nsol+=1;
}

void DFS(int x)
{
    lvl[x]=lvl[par[x]]+1;
    low[x]=lvl[x];
    for(int i=0;i<graph[x].size();++i)
    {
        if(!lvl[graph[x][i]])
        {
            par[graph[x][i]]=x;
            temp.push(make_pair(x,graph[x][i]));
            DFS(graph[x][i]);
            if(low[graph[x][i]]>=lvl[x])
                RegisterSol(x,graph[x][i]);
        }
        if(low[graph[x][i]]<low[x]&&graph[x][i]!=par[x])
            low[x]=low[graph[x][i]];
    }

}

int main()
{
    scanf("%d%d",&n,&m);

    for(int i=0;i<m;++i)
    {
        int x,y;
        scanf("%d%d",&x,&y);

        graph[x].push_back(y);
        graph[y].push_back(x);
    }

    for(int i=1;i<=n;++i)
        if(!lvl[i])
            DFS(i);

    printf("%d\n",nsol);

    for(int i=0;i<nsol;++i)
    {
        for(int j=0;j<sol[i].size();++j)
        {
            printf("%d ",sol[i][j]);
        }
        printf("\n");
    }

    return 0;
}