//componente biconexe

#include <bits/stdc++.h>
using namespace std;
 
int n, m, Sol;
int low[100005], lev[100005];
vector <int> v[100005];
vector <int> C[100005];
stack <pair <int, int> > st;
inline void cb(int x, int y){
    int a, b;
    do{
        a = st.top().first;
        b = st.top().second;
        st.pop();
        C[Sol].push_back(b);
    }while(!(a == x && b == y));
    C[Sol].push_back(a);
}
inline void dfs(int nod, int TT, int k){
    low[nod] = lev[nod] = k;
    for(auto it : v[nod]){
        if(it != TT){
            if(lev[it] == 0){
                st.push(make_pair(nod, it));
                dfs(it, nod, k + 1);
                if(lev[nod] <= low[it]){
                    ++Sol;
                    cb(nod, it);
                }
                low[nod] = min(low[nod], low[it]);
            }
            else low[nod] = min(low[nod], lev[it]);
        }
 
    }
}
int main()
{
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    scanf("%d%d", &n, &m);
    int x, y;
    for(int i = 1; i <= m ; ++i){
        scanf("%d%d", &x, &y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1, 0, 1);
    printf("%d\n", Sol);
    for(int i = 1; i <= Sol ; ++i){
        sort(C[i].begin(), C[i].end());
        for(auto it : C[i]) printf("%d ", it);
        printf("\n");
    }
    return 0;
}