#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
const ll LOG = 31;
const ll MOD = 1000000007;
const ll inf = 1e17;
const ll B = 2305843009213693951;
#define db(x) cerr << #x << " = " << x << " | "
#define dbg(x) cerr << #x << " = " << x << "\n"
#define Algerian ios::sync_with_stdio(0);
#define OI cin.tie(NULL);
int main() {
Algerian OI
ll n, m;
cin >> n >> m;
vector<vector<ll>> adj(n);
for (ll i = 0; i < n; i++) {
ll u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
cout << 2 * (n - 1) << "\n";
for (ll i = n; i >= 2; i--) {
for (ll j = 1; j <= i; j++) cout << "0 ";
for (ll j = i + 1; j <= n; j++) cout << j << " \n"[j == n];
}
return 0;
}
