#include <bits/stdc++.h>

using namespace std;

#if 1
#define pv(x) cout<<#x<<" = "<<x<<"; ";cout.flush()
#define pn cout<<endl
#else
#define pv(x)
#define pn
#endif

ifstream in("biconex.in");
ofstream out("biconex.out");

using ll = long long;
using ull = unsigned long long;
using ui = unsigned int;
#define pb push_back
#define mp make_pair
const int NMax = 1e5 + 5;
const int inf = 1e9 + 5;
const int mod = 100003;
using zint = int;

int N,M,nrComp;
int lowPoint[NMax],depth[NMax];
vector<int> v[NMax], comp[NMax];

void dfs(int);
void getComp(pair<int,int>);

int main() {
    in>>N>>M;
    for (int i = 1;i <= M;++i) {
        int x,y;
        in>>x>>y;

        v[x].pb(y);
        v[y].pb(x);
    }

    for (int i = 1;i <= N;++i) {
        if (depth[i]) {
            continue;
        }

        depth[i] = 1;
        dfs(i);
    }

    /*
    for (int i = 1;i <= N;++i) {
        pv(i);pv(depth[i]);pn;
    }
    //*/

    out<<nrComp<<'\n';
    for (int i = 1;i <= nrComp;++i) {
        for (int node : comp[i]) {
            out<<node<<' ';
        }
        out<<'\n';
    }

    in.close();out.close();
    return 0;
}

stack< pair<int,int> > st;
void dfs(int node) {
    lowPoint[node] = depth[node];

    for (int nxt : v[node]) {
        if (depth[nxt]) {
            lowPoint[node] = min(lowPoint[node], depth[nxt]);
            continue;
        }

        st.push( {node,nxt} );
        depth[nxt] = depth[node] + 1;
        dfs(nxt);
        lowPoint[node] = min(lowPoint[node], lowPoint[nxt]);

        if (lowPoint[nxt] == depth[node]) {
            ++nrComp;
            getComp( {node,nxt} );
        }
    }
}

void getComp(pair<int,int> m) {
    while (st.top() != m) {
        comp[nrComp].pb( st.top().second );
        st.pop();
    }

    comp[nrComp].pb( m.second );
    comp[nrComp].pb( m.first );

    st.pop();
}