#include <cstdio>
#include <cstring>

#include <iostream>
#include <set>
#include <stack>
#include <vector>

using namespace std;

const int MAXN = 100001;

int n, m;
int dfn[MAXN];
int low[MAXN];

vector<int> G[MAXN];
vector<set<int> > sols;
stack<pair<int, int> > st;

void recover(int x, int y)
{
    set<int> sol;
    int tx, ty;
    do {
        tx = st.top().first;
        ty = st.top().second;
        st.pop();
        sol.insert(tx);
        sol.insert(ty);
    } while (x != tx && y != ty);

    sols.push_back(sol);
}

void dfs(int prev, int node, int num)
{
    low[node] = dfn[node] = num;
    for (int i = 0; i < G[node].size(); ++i) {
        int next = G[node][i];
        if (prev == next)
            continue;
        if (dfn[next] == -1) {
            st.push(make_pair(node, next));
            dfs(node, next, num + 1);
            low[node] = min(low[node], low[next]);
            if (low[next] >= dfn[node])
                recover(node, next);
        } else {
            low[node] = min(low[node], low[next]);
        }
    }
}

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

    scanf("%d %d", &n, &m);
    for (int i = 0; i < m; ++i) {
        int x, y;
        scanf("%d %d", &x, &y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    
    memset(dfn, -1, sizeof(dfn));
    for (int i = 1; i <= n; ++i) 
        if (dfn[i] == -1)
            dfs(0, i, 0);

    printf("%lu\n", sols.size());
    for (int i = 0; i < sols.size(); ++i) {
        set<int>::iterator it;
        for (it = sols[i].begin(); it != sols[i].end(); ++it) 
            printf("%d ", *it);
        printf("\n");
    }

    return 0;
}