#include <cstdio>
#include <deque>
#include <vector>
#include <algorithm>
using namespace std;
deque<int> st;
vector<int> g[100005];
struct Nod
{
    int disc,low;
} v[100005];
vector<int> sol[100005];
bool viz[100005];
int nr,k;
void dfs(int nod)
{
    v[nod].disc=++nr;
    v[nod].low=nr;
    st.push_back(nod);
    viz[nod]=1;
    for(int i=0; i<g[nod].size(); i++){
        if(viz[g[nod][i]]==0){
            dfs(g[nod][i]);
            v[nod].low=min(v[nod].low, v[g[nod][i]].low);
        }
        else{
            if(g[nod][i]!=nod)
                v[nod].low=min(v[nod].low, v[g[nod][i]].disc);
            continue;
        }
        if(v[g[nod][i]].low>=v[nod].disc){
            ++k;
            int x;
            do{
                x=st.back();
                sol[k].push_back(st.back());
                st.pop_back();
            }while(x!=g[nod][i]);
            sol[k].push_back(nod);
        }
    }
}
int main()
{   freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    int n,m,i,x,y,j;
    scanf("%d%d", &n, &m);
    for(i=1; i<=m; i++){
        scanf("%d%d", &x, &y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for(i=1; i<=n; i++)
        if(viz[i]==0)
            dfs(i);
    printf("%d\n", k);
    for(i=1; i<=k; i++){
        for(j=0; j<sol[i].size(); j++)
            printf("%d ", sol[i][j]);
        printf("\n");
    }
    return 0;
}