#include <bits/stdc++.h>

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n,m,h[100005],low[100005],cnt;
vector<int> muchii[100005],cmp[100005];
bool use[100005];
stack<int> s;
void comp(int curent, int nxt)
{
    cnt++;
    while(s.top()!=nxt)
    {
        cmp[cnt].push_back(s.top());
        s.pop();
    }
    cmp[cnt].push_back(nxt);
    cmp[cnt].push_back(curent);
    s.pop();
}
void dfs(int nod,int father,int height)
{
    low[nod]=h[nod]=height;
    s.push(nod);
    for(auto i:muchii[nod])
    {
        if(!h[i])
        {
            dfs(i,nod,height+1);
            low[nod]=min(low[nod],low[i]);
            if(low[i]>=height)
                comp(nod,i);
        }
        else if(i!=father)
            low[nod]=min(low[nod],h[i]);
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    fin.tie(0);
    fout.tie(0);
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int a,b;
        fin>>a>>b;
        muchii[a].push_back(b);
        muchii[b].push_back(a);
    }
    for(int i=1;i<=n;i++)
        if(!h[i])
            dfs(i,-1,1);
    fout<<cnt<<'\n';
    for(int i=1;i<=cnt;i++)
    {
        for(auto j:cmp[i])
            fout<<j<<' ';
        fout<<'\n';
    }
    return 0;
}