#include <bits/stdc++.h>
using namespace std;
int n;
vector<int> res[100010];
inline int check() {
  int l = 2, r = n;
  while (l <= r) {
    int mid = (l + r) >> 1;
    if (1LL * mid * (mid - 1) / 2 <= n)
      l = mid + 1;
    else
      r = mid - 1;
  }
  return (l - 1);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  int tmp = check(), cnt = 0;
  for (int i = 1; i <= tmp - 1; ++i) {
    for (int j = i + 1; j <= tmp; ++j) {
      res[i].push_back(++cnt);
      res[j].push_back(cnt);
    }
  }
  cout << tmp << "\n";
  for (int i = 1; i <= tmp; ++i) {
    for (int j = 0; j <= res[i].size() - 1; ++j) cout << res[i][j] << ' ';
    cout << "\n";
  }
  return 0;
}
