#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int const N = 1e5 + 3;
int n , m , timp , biconexe;
int tin[N] , low[N] , viz[N];
vector<int> v[N];
vector<pair<int , int> > bcx_m[N];
vector<int> bcx[N];
stack<pair<int , int> > st;
void dfs(int x , int p = -1){
    viz[x] = 1;
    tin[x] = low[x] = ++timp;
    int fii(0);
    for(int y : v[x]){
        if(y == p) continue;
        if(viz[y]){
            low[x] = min(low[x] , tin[y]);
            if(tin[y] < tin[x]){
                st.emplace(x , y);
            }
        }else{
            ++ fii;
            st.emplace(x , y);
            dfs(y , x);
            low[x] = min(low[x] , low[y]);
            if(p != -1 && low[y] >= tin[x]){
                ++ biconexe;
                int a , b;
                do{
                    a = st.top().fi , b = st.top().se;
                    bcx_m[biconexe].push_back(st.top());
                    st.pop();
                }while(!(a == x && b == y));
            }
        }
    }
    if(p == -1 && fii > 1){
        ++ biconexe;
        int a , b;
        do{
            a = st.top().fi , b = st.top().se;
            bcx_m[biconexe].push_back(st.top());
            st.pop();
        }while(a != x);
    }
}
int main()
{
    fin >> n >> m;
    for(int i = 1 ; i <= m ; ++ i){
        int a , b;
        fin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for(int i = 1 ; i <= n ; ++ i){
        if(!viz[i]){
            dfs(i);
            if(!st.empty()){
                ++ biconexe;
                while(!st.empty()){
                    bcx_m[biconexe].push_back(st.top());
                    st.pop();
                }
            }
        }
    }
    for(int i = 1 ; i <= biconexe ; ++ i){
        vector<int> bcn;
        for(auto y : bcx_m[i]){
            bcn.push_back(y.fi);
            bcn.push_back(y.se);
        }
        sort(bcn.begin() , bcn.end());
        bcn.erase(unique(bcn.begin() , bcn.end()) , bcn.end());
        bcx[i] = bcn;
    }
    fout << biconexe << '\n';
    for(int i = 1 ; i <= biconexe ; ++ i){
        for(int y : bcx[i])
            fout << y << ' ';
        fout << '\n';
    }
    return 0;
}