#include<bits/stdc++.h>
//#include<atcoder/all>
using namespace std;
//using namespace atcoder;
#define rep(i,n) for(ll i=0; i<n; i++)
#define rrep(i,n) for(ll i=n-1; i>=0; i--)
#define print(a) cout<<a<<endl
typedef long long ll;
#define yn(flg) if(flg){cout<<"Yes"<<endl;}else{cout<<"No"<<endl;}
#define YN(flg) if(flg){cout<<"YES"<<endl;}else{cout<<"NO"<<endl;}
#define so(a) sort(a.begin(),a.end())
#define mp make_pair
#define vi vector<int>
#define vl vector<ll>
#define vs vector<string>
#define pb push_back
#define a2i(a,s) (ll)(a-s)
#define i2a(s,a) (char)(s+a)
#define ssize(a) a.size()
typedef pair<int, int> Pii;
typedef pair<int, ll> Pil;
typedef pair<pair<ll,ll>,ll> P3;
typedef pair<pair<ll,ll>,pair<ll,ll>> P4;
typedef pair<ll, ll> Pll;
typedef pair<ll,Pll> Plll;
typedef pair<Pii, int> Piii;
const ll INF = 1000000000000000000;
template<class T> inline bool chmin(T& a, T b) {
if (a > b) {
a = b;
return true;
}
return false;
}
template<class T> inline bool chmax(T& a, T b) {
if (a < b) {
a = b;
return true;
}
return false;
}
using ull=unsigned long long;
int main(){
//入力
cin.tie(0);
ios::sync_with_stdio(0);
ll n;
cin>>n;
vector<Pll> g(n);
map<Pll,ll> mp;
map<ll,ll> mp2;
for(ll i=0;i<n;i++){
ll a,b;
cin>>a>>b;
if(a>b)swap(a,b);
g[i]={a,b};
ll p=(b-a)/2;
if((b-a)%2==1){
ll P=(a+2*n-b)/2;
mp[{(a+p)%(2*n),(a+p+1)%(2*n)}]++;
mp[{(b+P)%(2*n),(b+P+1)%(2*n)}]++;
}
mp2[a]=i;
mp2[b]=i;
}
ll ans=-INF;
Pll p={0,0};
for(ll i=0;i<2*n-1;i++){
if(ans<mp[{i,i+1}]){
ans=mp[{i,i+1}];
p={i,i+1};
}
}
if(ans<mp[{2*n-1,0}]){
ans=mp[{2*n-1,0}];
p={2*n-1,0};
}
cout<<n-ans<<endl;
//判定
vector<ll> v(n);
vector<ll> V(2*n);
map<ll,ll> mp3;
for(ll i=0;i<n;i++){
mp3[p.first]=p.second;
mp3[p.second]=p.first;
p.second++;
p.first--;
p.second=p.second%(2*n);
p.first=(p.first+2*n)%(2*n);
}
for(ll i=0;i<n;i++){
if(v[i]==0){
v[i]=1;
ll X=mp3[g[i].first];
if(X==g[i].second){
V[g[i].first]=1;
V[g[i].second]=1;
continue;
}
V[g[i].first]=1;
cout<<i<<" "<<g[i].second<<" "<<X<<endl;
V[X]=1;
X=g[i].second;
while(true){
ll nx=mp3[X];
ll ny=mp2[nx];
v[ny]=1;
V[nx]=1;
V[X]=1;
if(g[ny].first==nx){
cout<<ny<<" "<<g[ny].second<<" "<<X<<endl;
X=g[ny].second;
}
else {
cout<<ny<<" "<<g[ny].first<<" "<<X<<endl;
X=g[ny].first;
}
if(V[X]==1)break;
}
}
}
return 0;
}
