#include <bits/stdc++.h>

using namespace std;

const int nmax = 1e5 + 10;

int n, m;
int used[nmax], low[nmax], lvl[nmax];
vector < int > g[nmax];
vector < pair < int, int > > st;
vector < vector < int > > ans;

void input() {
    scanf("%d %d", &n, &m);
    for (int i = 1; i <= m; ++i) {
        int x, y;
        scanf("%d %d", &x, &y);

        g[x].push_back(y);
        g[y].push_back(x);
    }
}

void get_biconex(pair < int, int > edge) {
    vector < int > res;
    while (true) {
        pair < int, int > curr = st.back(); st.pop_back();
        res.push_back(curr.second);

        if (curr == edge) break;
    }

    res.push_back(edge.first);
    ans.push_back(res);
}

void dfs(int node) {
    used[node] = 1;

    low[node] = lvl[node];
    for (auto &it: g[node]) {
        if (used[it]) {
            low[node] = min(low[node], lvl[it]);
            continue;
        }

        st.push_back({node, it});
        lvl[it] = lvl[node] + 1;

        dfs(it);

        if (low[it] >= lvl[node])
            get_biconex({node, it});
        low[node] = min(low[node], low[it]);
    }
}

void output() {
    printf("%d\n", (int)ans.size());
    for (int i = 0; i < (int)ans.size(); ++i, printf("\n"))
        for (auto &it: ans[i])
            printf("%d ", it);
}

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

    input();
    dfs(1);
    output();

    return 0;
}