#define _CRT_SECURE_NO_WARNINGS

#include <algorithm>
#include <bitset>
#include <cassert>
#include <chrono>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <initializer_list>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <stdexcept>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

#define ll long long
#define ull unsigned long long
#define ld long double
#define sz(a) (int) a.size()

const int inf = (int)1e9;
const ll linf = (ll)2e18;

const ll mod = (ll)1e9 + 7ll;

void solve() {
	int n; cin >> n;

	n = (n - 1) / 3;

	cout << n << "\n";
	vector<vector<int>> ans;

	while (n >= 4) {
		int t = (3 * n + 6) / 5;

		for (int a = 3 * n - 3 * t + 2; a <= 3 * n - 2 * t + 1; ++a) {
			ans.push_back({a, a + t, a + 2 * t});
		}

		n -= t;
	}

	if (n == 3) {
		ans.push_back({ 2, 9, 10 });
		ans.push_back({ 3, 5, 7 });
		ans.push_back({ 4, 6, 8 });
	}
	else if (n == 2) {
		ans.push_back({ 2, 4, 5 });
		ans.push_back({ 3, 6, 7 });
	}
	else if (n == 1) {
		ans.push_back({2, 3, 4});
	}

	for (int i = 0; i < sz(ans); ++i) {
		cout << ans[i][0] << " " << ans[i][1] << " " << ans[i][2] << "\n";
	}
}
	

signed main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
	//freopen("test.in", "r", stdin);
	//freopen("test.in", "w", stdout);
	//cout << fixed << setprecision(7);

	//clock_t start = clock();

	int tet = 1;
	//cin >> tet;
	while (tet--) {
		solve();
	}

	//clock_t end = clock();
	//ld seconds = (ld)(end - start) / CLOCKS_PER_SEC;
	//cout << seconds << "\n";
}