#include <bits/stdc++.h>

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

const int NMax = 100003;

int n,m,x,y,top,nr;
int low[NMax],s[NMax],viz[NMax];
vector<int> ans[NMax],G[NMax];

void dfs(int nod, int tata){
    viz[nod] = viz[tata] + 1;
    low[nod] = viz[nod];

    s[++top] = nod;

    for(int i = 0; i < G[nod].size(); ++i){
        if(G[nod][i] != tata){
            if(!viz[G[nod][i]]){
                dfs(G[nod][i],nod);

                low[nod] = min(low[nod],low[G[nod][i]]);


                if(low[G[nod][i]] >= viz[nod]){
                    nr++;
                    while(s[top] != G[nod][i]){
                        ans[nr].push_back(s[top]);
                        top--;
                    }
                    ans[nr].push_back(G[nod][i]);
                    top--;
                    ans[nr].push_back(nod);
                }


            }else
                low[nod] = min(low[nod],viz[G[nod][i]]);
        }
    }
}
int main()
{
    f >> n >> m;
    for(int i = 1; i <= m; ++i){
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1,0);
    g << nr << '\n';
    for(int i = 1; i <= nr; ++i){
        for(int j = 0; j < ans[i].size(); ++j){
            g << ans[i][j] << ' ';
        }
        g << '\n';
    }
    return 0;
}