#include <bits/stdc++.h>

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int const N = 1e5 + 3;
int n , m , a , b;
int idx[N] , low[N];
vector<int> v[N];
vector<vector<int> > comp;
stack<pair<int , int> > st;
void dfs(int x , int t){
    idx[x] = low[x] = ++idx[0];
    int fii(0);
    for(int& y : v[x]){
        if(y == t) continue;
        if(!idx[y]){
            ++fii;
            st.emplace(x , y);
            dfs(y , x);
            low[x] = min(low[x] , low[y]);
            if((x == 1 && fii > 1) || (x != 1 && low[y] >= idx[x])){
                vector<int> c;
                while(!(st.top().first == x && st.top().second == y)){
                    c.push_back(st.top().first) , c.push_back(st.top().second);
                    st.pop();
                }
                c.push_back(x) , c.push_back(y);
                st.pop();
                comp.push_back(c);
            }
        }else{
            low[x] = min(low[x] , idx[y]);
            if(idx[y] < idx[x])
                st.emplace(x , y);
        }
    }
}
int main()
{
    fin >> n >> m;
    for(int i = 1 ; i <= m ; ++ i){
        fin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for(int i = 1 ; i <= n ; ++ i){
        if(idx[i]) continue;
        dfs(i , 0);
        if(!st.empty()){
            vector<int> c;
            while(!st.empty()){
                c.push_back(st.top().first) , c.push_back(st.top().second);
                st.pop();
            }
            comp.push_back(c);
        }
    }
    fout << comp.size() << '\n';
    for(auto& x : comp){
        sort(x.begin() , x.end());
        auto last = unique(x.begin() , x.end());
        x.erase(last , x.end());
        for(int& y : x)
            fout << y << ' ';
        fout << '\n';
    }
    return 0;
}