#include <fstream>
#include <vector>
#include <algorithm>
#include <stack>

using namespace std;
ifstream cin("biconex.in");
ofstream cout("biconex.out");
int n,m;
int idx[100005],low[100005],T[100005],cnt;
vector<int> G[100005],c;
vector<vector<int>> cbc;
stack<pair<int,int>> stk;
void ExtractCbc(int x,int y)
{
    c.clear();
    while(!stk.empty())
    {
        auto [a,b]=stk.top();
        stk.pop();
        c.emplace_back(a);
        c.emplace_back(b);
        if(x==a && y==b)
            break;
    }
    cbc.emplace_back(c);
}
void Tarjan(int x)
{
    low[x]=idx[x]=++cnt;
    for(auto y:G[x])
    {
        if(y==T[x])
            continue;
        if(!idx[y])
        {
            T[y]=x;
            stk.emplace(x,y);
            Tarjan(y);
            low[x]=min(low[x],low[y]);
            if(low[y]>=idx[x])
                ExtractCbc(x,y);
        }
        else
            low[x]=min(low[x],idx[y]);
    }
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        cin>>x>>y;
        G[x].emplace_back(y);
        G[y].emplace_back(x);
    }
    for(int i=1;i<=n;i++)
        if(!idx[i])
            Tarjan(i);
    cout<<cbc.size()<<"\n";
    for(auto &c:cbc)
    {
        sort(c.begin(),c.end());
        c.erase(unique(c.begin(),c.end()),c.end());
        for(auto x:c)
            cout<<x<<" ";
        cout<<"\n";
    }
    return 0;
}