#include <bits/stdc++.h>

using namespace std;

ifstream f("biconex.in");
ofstream g("biconex.out");

int n,m,x,y,comp,nivel[100200],nma[100200];
vector <int> edges[100200],biconex[100200];
stack <int> st;

void dfs(int x,int t)
{
    st.push(x);
    nivel[x]=nma[x]=nivel[t]+1;
    for(auto y:edges[x])
    {
        if(y!=t)
            if(nivel[y]==0)
                dfs(y,x), nma[x]=min(nma[x],nma[y]);
            else
                nma[x]=min(nma[x],nivel[y]);
    }
    if(nivel[t]<=nma[x] and t!=0)
    {
        comp++;
        while(!st.empty() and st.top()!=x)
            biconex[comp].push_back(st.top()), st.pop();
        st.pop();
        biconex[comp].push_back(x);
        biconex[comp].push_back(t);
    }
}

int main()
{
    f>>n>>m;
    for(int i=1; i<=m; i++)
        f>>x>>y, edges[x].push_back(y), edges[y].push_back(x);
    dfs(1,0);
    g<<comp<<'\n';
    for(int i=1; i<=comp; i++, g<<'\n')
        for(auto it:biconex[i])
            g<<it<<' ';
    return 0;
}