#include <bits/stdc++.h>
#define ll long long
#define cheat ios::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define cyes cout<<"Yes"<<endl
#define cno cout<<"No"<<endl
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define fe first
#define se second
#define int long long

using namespace std;

struct tripple{
    int a;
    int b;
    int c;
};


signed main(){
    int n;
    cin >> n;
    vector<int> sqr(n+1);
    for(int i=1;i<n+1;++i){
        sqr[i]=i*i;
    }
    vector<tripple> ans;
    ans.reserve(n/3);
    int a=(n-1)/3+1;
    int b=n-1;
    int c=n;
    while(a>1){
        while(sqr[c]-sqr[b]<=sqr[a]){
            --b;
        }
        int dif=c-b;
        for(int i=0;i<dif;++i){
            ans.push_back({a-i,b-i,c-i});
        }
        a-=dif;
        c=b-dif;
        b=c-1;
    }
    cout << (n-1)/3 << "\n";
    for(auto& x : ans){
        cout << x.a << " " << x.b << " " << x.c << "\n";
    }

}