#include <bits/stdc++.h>
#define MAXN 100010

inline int min(int a, int b){return a < b ? a : b;}
int n, m, a, b;
std::vector <std::vector <int>> M;
std::vector <int> G[1 + MAXN], emptyVec;
std::stack <std::pair<int, int>> S;
int depth[1 + MAXN], lowlink[1 + MAXN];
void writeComponent(int node){
    bool ok = 1;
    M.push_back(emptyVec);
    while(ok){
        if(S.top().second == node) ok = 0;
        M[M.size() - 1].push_back(S.top().first);
        S.pop();
    }
    M[M.size() - 1].push_back(node);
}
void tarjan(int node, int fth){
    depth[node] = lowlink[node] = depth[fth] + 1;
    for(auto y: G[node]){
        if(!depth[y]){
            S.push({y, node});
            tarjan(y, node);
            lowlink[node] = min(lowlink[node], lowlink[y]);
            if(lowlink[y] >= depth[node]) writeComponent(node);
        }
        else lowlink[node] = min(lowlink[node], depth[y]);
    }
}

int main(){
    FILE*fi,*fo;
    fi = fopen("biconex.in","r");
    fo = fopen("biconex.out","w");

    fscanf(fi,"%d%d", &n, &m);
    for(int i = 1; i <= m; i++){
        fscanf(fi,"%d%d", &a, &b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
    for(int i = 1; i <= n; i++) if(!depth[i]) tarjan(i, 0);
    fprintf(fo,"%d\n", M.size());
    for(int i = 0; i < M.size(); i++){
        for(int j = 0; j < M[i].size(); j++) fprintf(fo,"%d ", M[i][j]);
        fprintf(fo,"\n");
    }

    return 0;
}