#ifndef HITONANODE_LOCAL
// #pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#endif

#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cmath>
#include <complex>
#include <deque>
#include <forward_list>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>


#include <iostream>
#include <string>
#include <utility>
#include <vector>

class JsonDumper {
    struct KeyValue {
        std::string key;
        std::string value;
    };

    std::vector<KeyValue> _items;

    bool dump_at_end = false;

public:
    JsonDumper(bool dump_at_end_ = false) : dump_at_end(dump_at_end_) {}

    ~JsonDumper() {
        if (dump_at_end) std::cout << dump() << std::endl;
    }

    void set_dump_at_end() { dump_at_end = true; }

    void operator()(const std::string &key, const std::string &value) {
        _items.push_back(KeyValue{key, "\"" + value + "\""});
    }

    template <class T> void operator()(const std::string &key, T value) {
        _items.push_back(KeyValue{key, std::to_string(value)});
    }

    std::string dump() const {
        std::string ret = "{\n";

        if (!_items.empty()) {
            for (const auto &[k, v] : _items) ret += "    \"" + k + "\": " + v + ",\n";

            ret.erase(ret.end() - 2);
        }

        ret += "}";
        return ret;
    }
} jdump;

#define ALL(x) (x).begin(), (x).end()
#define FOR(i, begin, end) for (int i = (begin), i##_end_ = (end); i < i##_end_; i++)
#define IFOR(i, begin, end) for (int i = (end)-1, i##_begin_ = (begin); i >= i##_begin_; i--)
#define REP(i, n) FOR(i, 0, n)
#define IREP(i, n) IFOR(i, 0, n)

template <typename T> bool chmax(T &m, const T q) { return m < q ? (m = q, true) : false; }
template <typename T> bool chmin(T &m, const T q) { return m > q ? (m = q, true) : false; }

int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); }
template <class T1, class T2> T1 floor_div(T1 num, T2 den) {
    return (num > 0 ? num / den : -((-num + den - 1) / den));
}
template <class T1, class T2> std::pair<T1, T2> operator+(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) {
    return std::make_pair(l.first + r.first, l.second + r.second);
}
template <class T1, class T2> std::pair<T1, T2> operator-(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) {
    return std::make_pair(l.first - r.first, l.second - r.second);
}
template <class T> std::vector<T> sort_unique(std::vector<T> vec) {
    sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end());
    return vec;
}
template <class T> int arglb(const std::vector<T> &v, const T &x) {
    return std::distance(v.begin(), std::lower_bound(v.begin(), v.end(), x));
}
template <class T> int argub(const std::vector<T> &v, const T &x) {
    return std::distance(v.begin(), std::upper_bound(v.begin(), v.end(), x));
}
template <class IStream, class T> IStream &operator>>(IStream &is, std::vector<T> &vec) {
    for (auto &v : vec) is >> v;
    return is;
}

template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec);
template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr);
template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec);
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec);
template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec);
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa);
template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp);
template <class OStream, class TK, class TV, class TH>
OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp);
template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl);

template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec) {
    os << '[';
    for (auto v : vec) os << v << ',';
    os << ']';
    return os;
}
template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr) {
    os << '[';
    for (auto v : arr) os << v << ',';
    os << ']';
    return os;
}
template <class... T> std::istream &operator>>(std::istream &is, std::tuple<T...> &tpl) {
    std::apply([&is](auto &&...args) { ((is >> args), ...); }, tpl);
    return is;
}
template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl) {
    os << '(';
    std::apply([&os](auto &&...args) { ((os << args << ','), ...); }, tpl);
    return os << ')';
}
template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec) {
    os << '{';
    for (auto v : vec) os << v << ',';
    os << '}';
    return os;
}
template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec) {
    os << "deq[";
    for (auto v : vec) os << v << ',';
    os << ']';
    return os;
}
template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec) {
    os << '{';
    for (auto v : vec) os << v << ',';
    os << '}';
    return os;
}
template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec) {
    os << '{';
    for (auto v : vec) os << v << ',';
    os << '}';
    return os;
}
template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec) {
    os << '{';
    for (auto v : vec) os << v << ',';
    os << '}';
    return os;
}
template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa) {
    return os << '(' << pa.first << ',' << pa.second << ')';
}
template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp) {
    os << '{';
    for (auto v : mp) os << v.first << "=>" << v.second << ',';
    os << '}';
    return os;
}
template <class OStream, class TK, class TV, class TH>
OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp) {
    os << '{';
    for (auto v : mp) os << v.first << "=>" << v.second << ',';
    os << '}';
    return os;
}

#ifdef HITONANODE_LOCAL
const std::string COLOR_RESET = "\033[0m", BRIGHT_GREEN = "\033[1;32m", BRIGHT_RED = "\033[1;31m",
                  BRIGHT_CYAN = "\033[1;36m", NORMAL_CROSSED = "\033[0;9;37m", RED_BACKGROUND = "\033[1;41m",
                  NORMAL_FAINT = "\033[0;2m";
#define dbg(x)                                                                                                        \
    std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") "        \
              << __FILE__ << COLOR_RESET << std::endl
#define dbgif(cond, x)                                                                                                \
    ((cond) ? std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__      \
                        << ") " << __FILE__ << COLOR_RESET << std::endl                                               \
            : std::cerr)
#else
#define dbg(x) 0
#define dbgif(cond, x) 0
#endif

#ifdef BENCHMARK
#define dump_onlinejudge(x) 0
struct setenv {
    setenv() { jdump.set_dump_at_end(); }
} setenv_;
#else
#define dump_onlinejudge(x) (std::cout << (x) << std::endl)
#endif
#include <array>
#include <cassert>
#include <cmath>
#include <cstdlib>
#include <vector>

using namespace std;
using lint = long long;
using pint = std::pair<int, int>;
using plint = std::pair<lint, lint>;

struct fast_ios {
    fast_ios() {
        std::cin.tie(nullptr), std::ios::sync_with_stdio(false), std::cout << std::fixed << std::setprecision(20);
    };
} fast_ios_;

constexpr int N = 45;

// void gen
constexpr lint AMIN = 100000000000000000;
constexpr lint AMAX = 1000000000000000000;
constexpr lint goalx = 500000000000000000;
constexpr lint goaly = 500000000000000000;

constexpr int MAXT = 50;


#include <cstdint>
#include <vector>

uint32_t rand_int() // XorShift random integer generator
{
    static uint32_t x = 123456789, y = 362436069, z = 521288629, w = 88675123;
    uint32_t t = x ^ (x << 11);
    x = y;
    y = z;
    z = w;
    return w = (w ^ (w >> 19)) ^ (t ^ (t >> 8));
}
double rand_double() { return (double)rand_int() / UINT32_MAX; }

template <class T> void shuffle_vec(std::vector<T> &vec) {
    for (int i = 1; i < (int)vec.size(); ++i) {
        const int j = rand_int() % (i + 1);
        std::swap(vec.at(i), vec.at(j));
    }
}

#include <chrono>
#include <random>

struct rand_int_ {
    using lint = long long;
    std::mt19937 mt;
    rand_int_() : mt(std::chrono::steady_clock::now().time_since_epoch().count()) {}
    lint operator()(lint x) { return this->operator()(0, x); } // [0, x)
    lint operator()(lint l, lint r) {
        std::uniform_int_distribution<lint> d(l, r - 1);
        return d(mt);
    }
} rnd;

double eval_diversity(const array<lint, N> &A, const array<lint, N> &B, const bitset<N> &alives, lint cx, lint cy) {

    const int Z = 60;
    // const double r = 0.9;
    const double dec = 2.0;
    vector<double> hi(Z, -1e18);
    vector<double> invdsum(Z);
    REP(i, A.size()) {
        if (!alives[i]) continue;
        const lint a = A.at(i);
        const lint b = B.at(i);
        const double theta = atan2(b - cy, a - cx);
        int z = (theta / (2 * M_PI) + 0.5) * Z;
        // z = (z % Z + Z) % Z;
        const double dist = max(abs(a - cx), abs(b - cy)) + 1;
        // chmax(hi.at(z), -log10(dist));
        invdsum.at(z) += 1.0 / dist;
    }

    REP(z, Z) {
        if (invdsum.at(z)) hi.at(z) = log10(invdsum.at(z));
    }

    REP(_, 2) {
        FOR(i, 1, Z) {
            chmax(hi.at(i), hi.at(i - 1) - dec);
        }
        chmax(hi.at(0), hi.at(Z - 1) - dec);

        IFOR(i, 1, Z) {
            chmax(hi.at(i - 1), hi.at(i) - dec);
        }
        chmax(hi.at(Z - 1), hi.at(0) - dec);
    }
    return accumulate(ALL(hi), 0.0);
}


int calc_score(lint max_v1v2) {
    if (!max_v1v2) return 2000000 + 50;
    double sol = 2000000 - 100000 * log10(max_v1v2 + 1);
    return floor(sol);
}


using SolutionState = vector<pint>;

double eval_l2(const array<long long, N> &Ainit, const array<long long, N> &Binit, const SolutionState &sol) {
    array<long long, N> A = Ainit, B = Binit;
    for (auto [i, j] : sol) {
        lint tmpa = (A.at(i) + A.at(j)) / 2;
        lint tmpb = (B.at(i) + B.at(j)) / 2;
        A.at(i) = A.at(j) = tmpa;
        B.at(i) = B.at(j) = tmpb;
    }
    const double dx = abs(A.at(0) - goalx), dy = abs(B.at(0) - goaly);
    return sqrt(dx * dx + dy * dy);
}

lint eval_linf(const array<long long, N> &Ainit, const array<long long, N> &Binit, const SolutionState &sol) {
    array<long long, N> A = Ainit, B = Binit;
    for (auto [i, j] : sol) {
        lint tmpa = (A.at(i) + A.at(j)) / 2;
        lint tmpb = (B.at(i) + B.at(j)) / 2;
        A.at(i) = A.at(j) = tmpa;
        B.at(i) = B.at(j) = tmpb;
    }
    const lint dx = abs(A.at(0) - goalx), dy = abs(B.at(0) - goaly);
    return max(dx, dy);
}

template <int D> struct ExponentialDistSampler {
    std::array<double, (1 << D)> logps;

    constexpr ExponentialDistSampler() {
        for (int i = 0; i < (1 << D); ++i) logps.at(i) = log((0.5 + i) / (1 << D));
    }

    double sample(uint32_t p) const { return logps.at(p & ((1 << D) - 1)); }

    // exp(-|dx| / T) >= p <=>  -|dx| >= log(p) * T, p ~ U(0, 1)
    bool operator()(double abs_dx, double T, uint32_t p) const { return -abs_dx >= logps.at(p & ((1 << D) - 1)) * T; }
};
const ExponentialDistSampler<16> log_ps;

struct Solver {
    array<long long, N> initA, initB;

    vector<pint> intro_ops;
    vector<pint> best_intro_ops;
    vector<int> after_intro;
    vector<int> best_after_intro;

    lint best_cost = 1LL << 62;

    void check_best() {
        if (chmin(best_cost, cost)) {
            best_intro_ops = intro_ops;
            best_after_intro = after_intro;
        }
    }

    array<long long, N> preprocessedA, preprocessedB;

    long long gx2, gy2;
    lint cost;

    static constexpr int E = 1;

    void precalc() {
        preprocessedA = initA;
        preprocessedB = initB;
        for (auto [i, j] : intro_ops) {
            lint tmpa = (preprocessedA.at(i) + preprocessedA.at(j)) / 2;
            lint tmpb = (preprocessedB.at(i) + preprocessedB.at(j)) / 2;
            preprocessedA.at(i) = preprocessedA.at(j) = tmpa;
            preprocessedB.at(i) = preprocessedB.at(j) = tmpb;
        }

        gx2 = preprocessedA.at(0) >> (after_intro.size() - E);
        gy2 = preprocessedB.at(0) >> (after_intro.size() - E);
        REP(d, after_intro.size()) {
            const int i = after_intro.at(d);
            gx2 += preprocessedA.at(i) >> (after_intro.size() - d - E);
            gy2 += preprocessedB.at(i) >> (after_intro.size() - d - E);
        }
        cost = max(abs((gx2 >> E) - goalx), abs((gy2 >> E) - goaly));
        check_best();
    }

    Solver(const array<long long, N> &A, const array<long long, N> &B) : initA(A), initB(B) {
        after_intro.resize(N - 1);
        REP(i, N - 1) after_intro.at(i) = i + 1;

        precalc();
    }

    bool swap2(int d, int e, double temp) {
        const int i = after_intro.at(d);
        const int j = after_intro.at(e);
        lint tmpgx2 = gx2 - (preprocessedA.at(i) >> (after_intro.size() - d - E)) +
                      (preprocessedA.at(j) >> (after_intro.size() - d - E));
        tmpgx2 += (preprocessedA.at(i) >> (after_intro.size() - e - E)) -
                  (preprocessedA.at(j) >> (after_intro.size() - e - E));

        lint tmpgy2 = gy2 - (preprocessedB.at(i) >> (after_intro.size() - d - E)) +
                      (preprocessedB.at(j) >> (after_intro.size() - d - E));

        tmpgy2 += (preprocessedB.at(i) >> (after_intro.size() - e - E)) -
                  (preprocessedB.at(j) >> (after_intro.size() - e - E));

        lint tmpcost = max(abs((tmpgx2 >> E) - goalx), abs((tmpgy2 >> E) - goaly));

        if (tmpcost <= cost or log_ps(log(1.0 * tmpcost / cost), temp, rand_int())) {
            swap(after_intro.at(d), after_intro.at(e));
            gx2 = tmpgx2;
            gy2 = tmpgy2;
            cost = tmpcost;
            check_best();
            return true;
        } else {
            return false;
        }
    }
};

// exp(-log10(tmpcost / cost) / temp) >= p
// -log10(tmpcost / cost) / temp >= log(p)
// - log(tmpcost / cost) >= log(p) * log(10) * temp

int main(int argc, char *argv[]) {

    {
        int n_;
        cin >> n_;
        assert(N == n_);
    }
    array<long long, N> A, B;
    {
        for (int i = 0; i < N; i++) {
            cin >> A.at(i) >> B.at(i);
        }
    }

    Solver solver(A, B);

    // auto A0 = A, B0 = B;

    // REP(_, 6) {
    //     lint maxdiff = 0;
    //     int a = 0, b = 0;
    //     REP(i, N) REP(j, i) {
    //         lint diff = max(abs(A0.at(i) - A0.at(j)), abs(B0.at(i) - B0.at(j)));
    //         if (chmax(maxdiff, diff)) {
    //             a = i, b = j;
    //         }
    //     }
    //     solver.intro_ops.emplace_back(a, b);
    //     lint tmpa = (A0.at(a) + A0.at(b)) / 2;
    //     lint tmpb = (B0.at(a) + B0.at(b)) / 2;
    //     A0.at(a) = A0.at(b) = tmpa;
    //     B0.at(a) = B0.at(b) = tmpb;
    // }

    // solver.precalc();

    const double Tbegin = 1 * log(10), Tend = 0.01 * log(10);

    constexpr int L = 10000000 * 2 / 10;

    // const double rT = pow(Tend / Tbegin, 1.0 / L);
    const double dT = (Tend - Tbegin) / L;

    REP(_, 10) {
        double T = Tbegin;

        REP(_, L) {
            // T *= rT;
            T += dT;

            int a = 0, b = 0;
            if (rand_double() < 0.2) {
                while (a == b) {
                    a = rand_int() % (N - 1);
                    b = rand_int() % (N - 1);
                }
            } else {
                const int s = rand_int() % 3 + 1;
                a = rand_int() % (N - 1 - s);
                b = a + s;
            }

            solver.swap2(a, b, T);
        }
        dbg(make_tuple(_, solver.cost, solver.best_cost));
    }

    vector<pint> best = solver.best_intro_ops;
    for (int i : solver.best_after_intro) {
        best.emplace_back(0, i);
    }

    dump_onlinejudge(best.size());
    for (auto [i, j] : best) {
        dump_onlinejudge(to_string(i + 1) + " " + to_string(j + 1));
    }


    const lint cost = eval_linf(A, B, best);
    const int score = calc_score(cost);
    jdump("score", score);
    dbg(cost);
    dbg(score);
}