#include <bits/stdc++.h>
using namespace std;
using namespace chrono;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#endif

int main() {
  const auto start = steady_clock::now();

  std::cin.tie(nullptr);
  std::ios_base::sync_with_stdio(false);

  int64_t n;
  cin >> n;
  vector<int64_t> as(n), bs(n);
  for (int64_t i = 0; i < n; i++) {
    cin >> as[i] >> bs[i];
  }

  random_device rnd;
  mt19937 engine(rnd());

  uniform_int_distribution<> randt(0, 45);
  uniform_int_distribution<> randn(0, n - 1);

  int64_t c = 500000000000000000LL;

  auto calc_score = [&] {
    return int64_t(2000000 -
                   100000 * log10(max(abs(as[0] - c), abs(bs[0] - c)) + 1));
  };

  vector<int64_t> us, vs;
  for (int64_t t = 0; t < 50; t++) {
    if (t % 2 == 0) {
      int64_t p = 1, q = 2;

      if (t != 49 && t < 2 * randt(engine)) {
        p = randn(engine);
        do {
          q = randn(engine);
        } while (p == q);
      } else {
        for (int64_t i = 1; i < n; i++) {
          for (int64_t j = i + 1; j < n; j++) {
            int64_t x = (as[i] + as[j]) / 2;
            int64_t y = (bs[i] + bs[j]) / 2;

            int64_t a = (as[p] + as[q]) / 2;
            int64_t b = (bs[p] + bs[q]) / 2;

            if (max(abs(as[0] + x) / 2 - c, abs(bs[0] + y) / 2 - c) <
                max(abs(as[0] + a) / 2 - c, abs(bs[0] + b) / 2 - c)) {
              p = i;
              q = j;
            }
          }
        }
      }

      int64_t x = (as[p] + as[q]) / 2;
      int64_t y = (bs[p] + bs[q]) / 2;

      as[p] = as[q] = x;
      bs[p] = bs[q] = y;

      us.push_back(p + 1);
      vs.push_back(q + 1);
    } else {
      int64_t i = 1;
      for (int64_t j = 2; j < n; j++) {
        if (max(abs((as[0] + as[j]) / 2 - c), abs((bs[0] + bs[j]) / 2 - c)) <
            max(abs((as[0] + as[i]) / 2 - c), abs((bs[0] + bs[i]) / 2 - c))) {
          i = j;
        }
      }

      int64_t x = (as[0] + as[i]) / 2;
      int64_t y = (bs[0] + bs[i]) / 2;

      as[0] = as[i] = x;
      bs[0] = bs[i] = y;

      us.push_back(1);
      vs.push_back(i + 1);
    }
  }

  cout << us.size() << '\n';
  for (int64_t i = 0; i < us.size(); i++) {
    cout << us[i] << ' ' << vs[i] << '\n';
  }

  cerr << calc_score() << endl;
  for (int64_t i = 0; i < n; i++) {
    cerr << as[i] << ' ' << bs[i] << endl;
  }

  return 0;
}