#include <bits/stdc++.h>
#define pb push_back

using namespace std;

int n, m, nd = 0, ans = 0, g = 0;
bool was[(int)1e5];
int arr[(int)1e5];
int mas[(int)1e5];

vector <vector<int>> gr;

void input(){
    int a, b;
    cin >> n >> m; // n - kolvo vershin, m - kolvo strok (reber)
    gr.resize(n+1);
    for(int i = 0; i < m; i++){
        cin >> a;
        cin >> b;
        gr[a].pb(b);
        gr[b].pb(a);
    }
}

void output(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int b = 0;
    cout << ans << endl;
    for(int i = 1; i <= ans; i++){
        cout << arr[i]  << endl;
        for(int j = b; j < arr[i]+b; j++){
            cout << mas[j] << " ";
        }
        cout << endl;
        b += arr[i];
    }
}

void dfs(int v){
    int to;
    nd++;
    mas[g] = v;
    g++;
    was[v] = true;
    int sz = gr[v].size();
    for(int j = 0; j < sz; j++){
        to = gr[v][j];
        if(!was[to]){
            dfs(to);
        }
    }
}

void solve(){
    int x;
    for(int i = 1; i <= n; i++){
        if(!was[i]){
            dfs(i);
            arr[ans+1] = nd;
            ans++;
        }
    }
    arr[0] = 0;
    for(int i = ans; i > 0; i--){
        x = arr[i] - arr[i-1];
        arr[i] = x;
    }
}

int main(){
    freopen("matrix.in", "r", stdin);
    freopen("matrix.out", "w", stdout);
    input();
    solve();
    output();
    return 0;
}