#include <bits/stdc++.h>
#define  NMAX 100005
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int n,m,viz[NMAX],v1[NMAX],v2[NMAX],k;
vector<int> G[NMAX],v[2*NMAX];
stack <int> s;
void dfs(int a)
{
    viz[a]=1;
    s.push(a);
    for(int i=0;i<G[a].size();i++)
    {
        int b=G[a][i];
        if(!viz[b])
        {
            v1[b]=v2[b]=v1[a]+1;
            dfs(b);
            if(v2[b]>=v1[a])
            {
                k++;
                while(s.top()!=b)
                {
                    v[k].push_back(s.top());
                    s.pop();
                }
                s.pop();
                v[k].push_back(b);
                v[k].push_back(a);
            }
            if(v2[b]<v2[a])
                v2[a]=v2[b];
        }
        else
            if(v1[b]<v2[a])
            v2[a]=v1[b];
    }
}
int main()
{
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(int i=1;i<=n;i++)
        if(!viz[i])
            dfs(i);
    g<<k<<"\n";
    for(int i=1;i<=k;i++)
    {
        for(int j=0;j<v[i].size();j++)
            g<<v[i][j]<<" ";
        g<<"\n";
    }
}