#include <bits/stdc++.h>
using namespace std;

int main() {
	// step #1. input
	int N;
	cin >> N;
	vector<double> A(N), B(N);
	for (int i = 0; i < N; i++) {
		cin >> A[i] >> B[i];
		A[i] -= 5.0e+17;
		B[i] -= 5.0e+17;
	}
	
	// step #2. construction
	double bestscore = 1.0e+99;
	vector<int> besttrack;
	for (int v1 = 1; v1 < N; v1++) {
		for (int v2 = v1 + 1; v2 < N; v2++) {
			double x = (A[0] + A[v1] + A[v2]) * 0.25;
			double y = (B[0] + B[v1] + B[v2]) * 0.25;
			vector<bool> used(N, false);
			used[0] = true;
			used[v1] = true;
			used[v2] = true;
			vector<int> track = { 0, v1, v2 };
			for (int level = 3; level <= N - 1; level++) {
				double mul = pow(0.5, level != N - 1 ? level : N - 2);
				double best = 1.0e+99;
				int pos = -1;
				for (int j = 0; j < N; j++) {
					if (!used[j]) {
						double d = max(abs(x + A[j] * mul), abs(y + B[j] * mul));
						if (best > d) {
							best = d;
							pos = j;
						}
					}
				}
				used[pos] = true;
				x += A[pos] * mul;
				y += B[pos] * mul;
				track.push_back(pos);
			}
			if (bestscore > max(abs(x), abs(y))) {
				bestscore = max(abs(x), abs(y));
				besttrack = track;
			}
		}
	}
	
	// step #3. output
	cout << N - 1 << endl;
	cout << besttrack[0] + 1 << ' ' << besttrack[1] + 1 << endl;
	for (int i = N - 2; i >= 2; i--) {
		cout << besttrack[i] + 1 << ' ' << besttrack[i + 1] + 1 << endl;
	}
	cout << besttrack[0] + 1 << ' ' << besttrack[2] + 1 << endl;
	
	return 0;
}