#include <iostream>
#include <cmath>
#include <ctime>
#include <vector>
#include <algorithm>
using namespace std;

const long long Target = 500000000000000000LL;
long long N;
long long A[59], C[59];
long long B[59], D[59];
long long Order[59];

long long GetScore() {
	for (int i = 1; i <= N; i++) C[i] = A[i];
	for (int i = 1; i <= N; i++) D[i] = B[i];
	for (int i = 1; i <= N - 1; i++) {
		long long avgC = (C[Order[i]] + C[Order[i + 1]]) / 2LL;
		long long avgD = (D[Order[i]] + D[Order[i + 1]]) / 2LL;
		C[Order[i]] = avgC; C[Order[i + 1]] = avgC;
		D[Order[i]] = avgD; D[Order[i + 1]] = avgD;
	}
	return max(abs(Target - C[1]), abs(Target - D[1]));
}

int main() {
	// Step 1. 入力
	cin >> N;
	for (int i = 1; i <= N; i++) cin >> A[i] >> B[i];

	// Step 2. 山登り法
	for (int i = 1; i <= N; i++) Order[i] = i;
	long long CurrentScore = GetScore();
	int StartTime = clock();
	while (true) {
		int idx1 = rand() % N + 1;
		int idx2 = rand() % N + 1;
		swap(Order[idx1], Order[idx2]);
		long long CandScore = GetScore();
		if (CurrentScore >= CandScore) {
			CurrentScore = CandScore;
		}
		else {
			swap(Order[idx1], Order[idx2]);
		}
		if (idx1 != 1 || idx2 != 2) continue;
		if (clock() - StartTime > 14 * CLOCKS_PER_SEC / 10) break;
	}

	// Step 3. 答えを得る
	vector<pair<int, int>> Answer;
	for (int i = 1; i <= N - 1; i++) Answer.push_back(make_pair(Order[i], Order[i + 1]));

	// Step 4. 出力
	cout << Answer.size() << endl;
	for (int i = 0; i < Answer.size(); i++) cout << Answer[i].first << " " << Answer[i].second << endl;
	return 0;
}