#include<bits/stdc++.h>
using namespace std;
#define pb push_back
typedef long long LL;
const int N = 1000011;
int vst[N];
vector<array<int, 3> > ans;
int main() {
	int n;
	scanf("%d", &n);
	if(n % 3 == 0) {
		n -= 2;
	}
	if(n % 3 == 2) {
		n -= 1;
	}
	if(n == 10) {
		ans.pb({4, 9, 10});
		ans.pb({3, 7, 8});
		ans.pb({2, 5, 6});
	}else {
		int m;
		int st;
		if((n / 3) % 2 == 1) {
			ans.pb({2, n - 1, n});
			m = n / 3 - 1;
			n -= 2;
			st = 3;
		}else {
			m = n / 3;
			st = 2;
		}

		int le[2], ri[2];
		le[0] = n - m * 2 + 1, ri[0] = n - m;
		le[1] = n - m + 1, ri[1] = n;
		for(int i = m - 1; i >= 0; i--) {
			ans.pb({st + i, le[i % 2], ri[i % 2]});
			le[i % 2]++;
			ri[i % 2]--;
		}
	}
	printf("%d\n", (int)ans.size());
	for(auto t : ans) {
		printf("%d %d %d\n", t[0], t[1], t[2]);
		assert(vst[t[0]] == false && vst[t[1]] == false && vst[t[2]] == false);
		vst[t[0]] = vst[t[1]] = vst[t[2]] = true;
		assert(t[0] + t[1] > t[2]);
		assert(t[0] < t[2] && t[1] < t[2]);
		assert((LL)t[0] * t[0] + (LL)t[1] * t[1] < (LL)t[2] * t[2]);
	}
}