#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<vector<int>> ans(N * 2 - 1);
  priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
  for (int i = 1; i <= N * 2 - 1; i++){
    int R = i;
    if (i % 2 == 1){
      ans[N * 2 - 2].push_back(i);
      R--;
    }
    if (i >= 2 && i <= N){
      R -= 2;
    }
    vector<pair<int, int>> P;
    for (int j = 0; j < R; j++){
      int p = pq.top().second;
      pq.pop();
      ans[p].push_back(i);
      P.push_back(make_pair(ans[p].size(), p));
    }
    for (auto P2 : P){
      pq.push(P2);
    }
    if (i >= 2 && i <= N){
      ans[i * 2 - 4].push_back(i);
      ans[i * 2 - 3].push_back(i);
      pq.push(make_pair(1, i * 2 - 4));
      pq.push(make_pair(1, i * 2 - 3));
    }
  }
  cout << N * 2 - 1 << endl;
  for (int i = 0; i < N * 2 - 1; i++){
    for (int j = 0; j < N; j++){
      cout << ans[i][j];
      if (j < N - 1){
        cout << ' ';
      }
    }
    cout << endl;
  }
}