#include <fstream>
#include <vector>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
const int nmax = 100005;
vector<int>ls[nmax], sol[nmax];
int n, m, i, j, x, y;
bool viz[nmax];
int niv[nmax], lmax[nmax];
int stiva[nmax], vf, comp;
void adaug(int x, int tt) {
sol[comp].push_back(tt);
while (stiva[vf] != x && vf > 0) {
sol[comp].push_back(stiva[vf]);
vf--;
}
if (vf > 0) {
sol[comp].push_back(x);
vf--;
}
}
void dfs(int x, int tt) {
int l = ls[x].size(), y, i;
lmax[x]=niv[x]=niv[tt]+1;
viz[x]=1;
for (i = 0; i < l; i++) {
y = ls[x][i];
if (y == tt) continue;
if (viz[y] == 1) {
lmax[x] = min(lmax[x], niv[y]);
continue;
}
stiva[++vf] = y;
dfs(y,x);
lmax[x] = min(lmax[x], lmax[y]);
if (niv[x] <= lmax[y]) {
comp++;
adaug(y, x);
}
}
}
int main() {
f >> n >> m;
for (i = 1; i <= m; i++) {
f >> x >> y;
ls[x].push_back(y);
ls[y].push_back(x);
}
for (i = 1; i <= n; i++)
if (viz[i] == 0) dfs(i,0);
g << comp << "\n";
for (i = 1; i <= comp; i++) {
for (j = 0; j < sol[i].size(); j++)
g << sol[i][j] << ' ';
g << '\n';
}
return 0;
}