#include <iostream>
#include <vector>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(NULL);
int N;
cin >> N;
vector<pair<int, int>> initial(N);
vector<int> count(2 * N, 0);
for (int i = 0; i < N; ++i) {
cin >> initial[i].first >> initial[i].second;
count[(initial[i].first + initial[i].second) % (2 * N)]++;
}
int best_s = 0;
for (int s = 0; s < 2 * N; ++s) {
if (count[s] > count[best_s]) best_s = s;
}
vector<int> pin_to_string(2 * N);
vector<pair<int, int>> current = initial;
for (int i = 0; i < N; ++i) {
pin_to_string[current[i].first] = i;
pin_to_string[current[i].second] = i;
}
struct Move { int p, s, e; };
vector<Move> moves;
// We process each pin i. If it's not connected to its symmetric partner j, fix it.
for (int i = 0; i < 2 * N; ++i) {
int j = (best_s - i + 2 * N) % (2 * N);
if (i >= j) continue; // Only process each pair once
int str_i = pin_to_string[i];
int str_j = pin_to_string[j];
if (str_i == str_j) continue; // Already parallel
// We need pin i and pin j to be the same string.
// Let's move the 'other' end of string i to pin j.
int other_of_i = (current[str_i].first == i) ? current[str_i].second : current[str_i].first;
// Record the move: move string str_i from 'other_of_i' to 'j'
moves.push_back({str_i, other_of_i, j});
// Update tracking
// The pin 'other_of_i' is now "empty" (or rather, str_i left it)
// String str_j no longer owns pin j
if (current[str_i].first == i) current[str_i].second = j;
else current[str_i].first = j;
pin_to_string[j] = str_i;
// Note: other_of_i is now "dangling" or will be claimed by another string later.
}
cout << moves.size() << "\n";
for (auto &m : moves) {
cout << m.p << " " << m.s << " " << m.e << "\n";
}
return 0;
}
