#include <fstream>
#include <vector>
#include <unordered_set>
#include <stack>
#include <algorithm>
using namespace std;
ifstream in("biconex.in");
ofstream out("biconex.out");
vector <int> v[100003];
struct ele
{
    int x,y;
    ele(int a, int b):x(a),y(b){}
    ele(){}
};
ele edge;
unordered_set<int> ms[100004];
stack <struct ele> s;
int niv[100004],nic[100004],nr=0,start;
bool viz[100004];
void DFS(int i)
{
    for(const int&j:v[i])
    {
        if(viz[j]==0)
        {
            s.push(ele(i,j));
            viz[j] = 1;
            niv[j]= niv[i]+1; nic[j]=niv[j];
            DFS(j);
            nic[i]= min(nic[j],nic[i]);
            if (nic[j] >= niv[i])
            {
                do
                {
                    edge = s.top();
                    s.pop();
                    ms[nr].insert(edge.x);
                    ms[nr].insert(edge.y);
                }
                while(!((edge.x==i &&edge.y==j) ||(edge.x==j &&edge.y==i)));
                nr++;
            }
        }
        else if (niv[j]<nic[i] && niv[j]!=niv[i]-1)
                nic[i] = niv[j];
    }
}
int main()
{
    int n,m,i,x,y;
    in>>n>>m;
    for(i=0;i<m;i++)
    {
        in>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    start = 1;
    niv[start]= nic[start]= viz[start]=1;
    DFS(start);//incepem dfs
    out<<nr<<"\n";
    for(i=0;i<nr;i++)
    {
        for(const int&e : ms[i])
            out<<e<<" ";
        out<<"\n";
    }
    return 0;
}