#include <iostream>
#include <fstream>
#include <stack>
#include <vector>
using namespace std;
ifstream in ("biconex.in");
ofstream out("biconex.out");
int n, m, x, y;
vector <int> vecini[100002];
vector < vector <int> > sol;
int height[100002];
int minHeight[100002];
stack <int> stk;
void dfs(int nod, int level){
    minHeight[nod]=height[nod]=level;
    stk.push(nod);
    for(auto &x:vecini[nod]){
        if(!height[x]){
            dfs(x, level+1);
            minHeight[nod]=min(minHeight[nod], minHeight[x]);

            if(minHeight[x]>=height[nod]){
                vector <int> act;
                int t;
                do{
                    t=stk.top();
                    stk.pop();
                    act.push_back(t);
                }while(t!=x);
                act.push_back(nod);
                sol.push_back(act);
            }
        }
        else if(height[x]!=height[nod]-1){
            minHeight[nod]=min(minHeight[nod], height[x]);
        }
    }
}
int main()
{
    in>>n>>m;
    for(int i=1; i<=m; i++){
        in>>x>>y;
        vecini[x].push_back(y);
        vecini[y].push_back(x);
    }
    dfs(1, 1);
    out<<sol.size()<<"\n";
    for(auto & vec:sol){
        for(auto & x:vec)
            out<<x<<" ";
        out<<"\n";
    }
    return 0;
}