#include <bits/stdc++.h>

using namespace std;
vector<int>nod[100005],mn,initial;
vector<vector<int> >ans;
int n,m,x,y;
stack<pair<int,int> >stk;
void make_biconex(int st,int dr)
{
    vector<int>aux;
    x=0,y=0;
    bitset<100005>ap;
    while(x!=st || y!=dr)
    {
        x=stk.top().first;
        y=stk.top().second;
        if(ap[x]==0)
        {
            ap[x]=1;
            aux.push_back(x);
        }
        if(ap[y]==0)
        {
            ap[y]=1;
            aux.push_back(y);
        }
        stk.pop();
    }
    ans.push_back(aux);
}
void node(int pos,int last,int val)
{
    mn[pos]=initial[pos]=val;
    vector<int>::iterator it;
    for(it=nod[pos].begin();it!=nod[pos].end();it++)
    {
        if(*it==last)
            continue;
        if(initial[*it]==-1)
        {
            stk.push({pos,*it});
            node(*it,pos,val+1);
            mn[pos]=min(mn[pos],mn[*it]);
            if(mn[*it]>=initial[pos])
                make_biconex(pos,*it);
        }
        else
            mn[pos]=min(mn[pos],initial[*it]);
    }
}
int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    scanf("%d %d\n",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d %d\n",&x,&y);
        nod[x].push_back(y);
        nod[y].push_back(x);
    }
    mn.resize(n+1);
    initial.resize(n+1);
    initial.assign(n+1,-1);
    node(1,0,0);
    printf("%d\n",ans.size());
    for(int i=0;i<ans.size();i++)
    {
        for(int j=0;j<ans[i].size();j++)
            printf("%d ",ans[i][j]);
        printf("\n");
    }
    return 0;
}