#include <vector>
#include <ctype.h>
#include <cstdio>
using namespace std;
const int NMAX=100100;
int x,y,n,m,comp,Niv[NMAX],Nma[NMAX],viz[NMAX],vf,S[NMAX];
vector<int>G[NMAX],CB[NMAX];

class InParser {
private:
    FILE *fin;
    char *buff;
    int sp;

    char read_ch() {
        ++sp;
        if(sp == 4096) {
            sp = 0;
            fread(buff, 1, 4096, fin);
        }
        return buff[sp];
    }

public:
    InParser(const char* nume) {
        fin = fopen(nume, "r");
        buff = new char[4096]();
        sp = 4095;
    }

    InParser& operator >> (int &n) {
        char c;
        while(!isdigit(c = read_ch()) && c != '-');
        int sgn = 1;
        if(c == '-') {
            n = 0;
            sgn = -1;
        } else {
            n = c - '0';
        }
        while(isdigit(c = read_ch())) {
            n = 10 * n + c - '0';
        }
        n *= sgn;
        return *this;
    }

    InParser& operator >> (long long &n) {
        char c;
        n = 0;
        while(!isdigit(c = read_ch()) && c != '-');
        long long sgn = 1;
        if(c == '-') {
            n = 0;
            sgn = -1;
        } else {
            n = c - '0';
        }
        while(isdigit(c = read_ch())) {
            n = 10 * n + c - '0';
        }
        n *= sgn;
        return *this;
    }
};


class OutParser {
private:
    FILE *fout;
    char *buff;
    int sp;

    void write_ch(char ch) {
        if(sp == 50000) {
            fwrite(buff, 1, 50000, fout);
            sp = 0;
            buff[sp++] = ch;
        } else {
            buff[sp++] = ch;
        }
    }


public:
    OutParser(const char* name) {
        fout = fopen(name, "w");
        buff = new char[50000]();
        sp = 0;
    }
    ~OutParser() {
        fwrite(buff, 1, sp, fout);
        fclose(fout);
    }

    OutParser& operator << (int vu32) {
        if(vu32 <= 9) {
            write_ch(vu32 + '0');
        } else {
            (*this) << (vu32 / 10);
            write_ch(vu32 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (long long vu64) {
        if(vu64 <= 9) {
            write_ch(vu64 + '0');
        } else {
            (*this) << (vu64 / 10);
            write_ch(vu64 % 10 + '0');
        }
        return *this;
    }

    OutParser& operator << (char ch) {
        write_ch(ch);
        return *this;
    }
    OutParser& operator << (const char *ch) {
        while(*ch) {
            write_ch(*ch);
            ++ch;
        }
        return *this;
    }
};

void DFS(int nod,int tata) {
    S[++vf]=nod;
    Niv[nod]=Niv[tata]+1;
    viz[nod]=1;
    Nma[nod]=Niv[nod];
    for(const int&i:G[nod]) {
        if(i==tata) {
            continue;
        }
        if(viz[i]==1) {
            Nma[nod]=min(Nma[nod],Niv[i]);
        } else {
            DFS(i,nod);
            Nma[nod]=min(Nma[nod],Nma[i]);
            if(Niv[nod]<=Nma[i]) {
                comp++;
                while(S[vf]!=i) {
                    CB[comp].push_back(S[vf--]);
                }
                CB[comp].push_back(i);
                vf--;
                CB[comp].push_back(nod);
            }
        }
    }
}


int main() {
    InParser f("biconex.in");
    OutParser g("biconex.out");
    f>>n>>m;
    while(m--) {
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    DFS(1,0);
    g<<comp<<'\n';
    for(int i=1; i<=comp; ++i) {
        for(const int &j:CB[i]) {
            g<<j<<' ';
        }
        g<<'\n';
    }
    return 0;
}