#include <bits/stdc++.h>

#define pb push_back
#define mp make_pair
#define st first
#define nd second
#define Min(A,B) (A < B ? A : B )

using namespace std;

const int Dim = 100001;

vector < int > G[Dim];
vector < vector< int > > Sol;
stack < pair < int,int > > S;
int N,M,D[Dim],L[Dim];

void DFS(int Node,int lvl,int P)
{
    D[Node] = L[Node] = lvl;

    for (int it = 0;it < G[Node].size();it++)
    {
        if (G[Node][it] == P)
            continue;

        if (!D[G[Node][it]])
        {
            S.push(mp(Node,G[Node][it]));
            DFS(G[Node][it],lvl + 1,Node);
            L[Node] = Min(L[Node],L[G[Node][it]]);

             if (L[G[Node][it]] >= D[Node])
             {
                 vector < int > Comp;
                 int X,Y;

                 do
                 {
                     X = S.top().st;
                     Y = S.top().nd;
                     S.pop();

                     Comp.pb(X);
                     Comp.pb(Y);

                 }while(X != Node && Y != G[Node][it]);

                 Sol.pb(Comp);
             }
        }
        else
            L[Node] = Min(L[Node],D[G[Node][it]]);
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);

     scanf("%d %d",&N,&M);

      while(M--)
      {
          int A,B;
          scanf("%d %d\n",&A,&B);
          G[A].pb(B);
          G[B].pb(A);
      }

    DFS(1,1,0);

    printf("%d\n",Sol.size());

    for (int i = 0;i < Sol.size();i++)
    {
        memset(D,0,sizeof(D));

        for (int j = 0;j < Sol[i].size();j++)
            if (!D[Sol[i][j]])
                 printf("%d ",Sol[i][j]),D[Sol[i][j]] = 1;

        printf("\n");
    }
}