/* #region Head */

// #include <bits/stdc++.h>
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert> // assert.h
#include <cmath>   // math.h
#include <cstring>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <memory>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pll = pair<ll, ll>;
template <class T> using vc = vector<T>;
template <class T> using vvc = vc<vc<T>>;
using vll = vc<ll>;
using vvll = vvc<ll>;
using vld = vc<ld>;
using vvld = vvc<ld>;
using vs = vc<string>;
using vvs = vvc<string>;
template <class T, class U> using um = unordered_map<T, U>;
template <class T> using pq = priority_queue<T>;
template <class T> using pqa = priority_queue<T, vc<T>, greater<T>>;
template <class T> using us = unordered_set<T>;

#define TREP(T, i, m, n) for (T i = (m), i##_len = (T)(n); i < i##_len; ++(i))
#define TREPM(T, i, m, n) for (T i = (m), i##_max = (T)(n); i <= i##_max; ++(i))
#define TREPR(T, i, m, n) for (T i = (m), i##_min = (T)(n); i >= i##_min; --(i))
#define TREPD(T, i, m, n, d) for (T i = (m), i##_len = (T)(n); i < i##_len; i += (d))
#define TREPMD(T, i, m, n, d) for (T i = (m), i##_max = (T)(n); i <= i##_max; i += (d))

#define REP(i, m, n) for (ll i = (m), i##_len = (ll)(n); i < i##_len; ++(i))
#define REPM(i, m, n) for (ll i = (m), i##_max = (ll)(n); i <= i##_max; ++(i))
#define REPR(i, m, n) for (ll i = (m), i##_min = (ll)(n); i >= i##_min; --(i))
#define REPD(i, m, n, d) for (ll i = (m), i##_len = (ll)(n); i < i##_len; i += (d))
#define REPMD(i, m, n, d) for (ll i = (m), i##_max = (ll)(n); i <= i##_max; i += (d))
#define REPI(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++)
#define REPIR(itr, ds) for (auto itr = ds.rbegin(); itr != ds.rend(); itr++)
#define ALL(x) begin(x), end(x)
#define SIZE(x) ((ll)(x).size())
#define ISIZE(x) ((int)(x).size())
#define PERM(c)                                                                                                        \
    sort(ALL(c));                                                                                                      \
    for (bool c##p = 1; c##p; c##p = next_permutation(ALL(c)))
#define UNIQ(v) v.erase(unique(ALL(v)), v.end());
#define CEIL(a, b) (((a) + (b)-1) / (b))

#define endl '\n'

constexpr ll INF = 1'010'000'000'000'000'017LL;
constexpr int IINF = 1'000'000'007LL;
constexpr ll MOD = 1'000'000'007LL; // 1e9 + 7
// constexpr ll MOD = 998244353;
constexpr ld EPS = 1e-12;
constexpr ld PI = 3.14159265358979323846;

template <typename T> istream &operator>>(istream &is, vc<T> &vec) { // vector 入力
    for (T &x : vec) is >> x;
    return is;
}
template <typename T> ostream &operator<<(ostream &os, const vc<T> &vec) { // vector 出力 (for dump)
    os << "{";
    REP(i, 0, SIZE(vec)) os << vec[i] << (i == i_len - 1 ? "" : ", ");
    os << "}";
    return os;
}
template <typename T> ostream &operator>>(ostream &os, const vc<T> &vec) { // vector 出力 (inline)
    REP(i, 0, SIZE(vec)) os << vec[i] << (i == i_len - 1 ? "\n" : " ");
    return os;
}

template <typename T, size_t _Nm> istream &operator>>(istream &is, array<T, _Nm> &arr) { // array 入力
    REP(i, 0, SIZE(arr)) is >> arr[i];
    return is;
}
template <typename T, size_t _Nm> ostream &operator<<(ostream &os, const array<T, _Nm> &arr) { // array 出力 (for dump)
    os << "{";
    REP(i, 0, SIZE(arr)) os << arr[i] << (i == i_len - 1 ? "" : ", ");
    os << "}";
    return os;
}

template <typename T, typename U> istream &operator>>(istream &is, pair<T, U> &pair_var) { // pair 入力
    is >> pair_var.first >> pair_var.second;
    return is;
}
template <typename T, typename U> ostream &operator<<(ostream &os, const pair<T, U> &pair_var) { // pair 出力
    os << "(" << pair_var.first << ", " << pair_var.second << ")";
    return os;
}

// map, um, set, us 出力
template <class T> ostream &out_iter(ostream &os, const T &map_var) {
    os << "{";
    REPI(itr, map_var) {
        os << *itr;
        auto itrcp = itr;
        if (++itrcp != map_var.end()) os << ", ";
    }
    return os << "}";
}
template <typename T, typename U> ostream &operator<<(ostream &os, const map<T, U> &map_var) {
    return out_iter(os, map_var);
}
template <typename T, typename U> ostream &operator<<(ostream &os, const um<T, U> &map_var) {
    os << "{";
    REPI(itr, map_var) {
        auto [key, value] = *itr;
        os << "(" << key << ", " << value << ")";
        auto itrcp = itr;
        if (++itrcp != map_var.end()) os << ", ";
    }
    os << "}";
    return os;
}
template <typename T> ostream &operator<<(ostream &os, const set<T> &set_var) { return out_iter(os, set_var); }
template <typename T> ostream &operator<<(ostream &os, const us<T> &set_var) { return out_iter(os, set_var); }
template <typename T> ostream &operator<<(ostream &os, const pq<T> &pq_var) {
    pq<T> pq_cp(pq_var);
    os << "{";
    if (!pq_cp.empty()) {
        os << pq_cp.top(), pq_cp.pop();
        while (!pq_cp.empty()) os << ", " << pq_cp.top(), pq_cp.pop();
    }
    return os << "}";
}

// tuple 出力
template <size_t N = 0, bool end_line = false, typename... Args> ostream &operator<<(ostream &os, tuple<Args...> &a) {
    if constexpr (N < std::tuple_size_v<tuple<Args...>>) {
        os << get<N>(a);
        if constexpr (N + 1 < std::tuple_size_v<tuple<Args...>>) {
            os << ' ';
        } else if constexpr (end_line) {
            os << '\n';
        }
        return operator<< <N + 1, end_line>(os, a);
    }
    return os;
}
template <typename... Args> void print_tuple(tuple<Args...> &a) { operator<< <0, true>(std::cout, a); }

void pprint() { std::cout << endl; }
template <class Head, class... Tail> void pprint(Head &&head, Tail &&...tail) {
    std::cout << head;
    if (sizeof...(Tail) > 0) std::cout << ' ';
    pprint(move(tail)...);
}

// dump
#define DUMPOUT cerr
void dump_func() { DUMPOUT << endl; }
template <class Head, class... Tail> void dump_func(Head &&head, Tail &&...tail) {
    DUMPOUT << head;
    if (sizeof...(Tail) > 0) DUMPOUT << ", ";
    dump_func(move(tail)...);
}

// chmax (更新「される」かもしれない値が前)
template <typename T, typename U, typename Comp = less<>> bool chmax(T &xmax, const U &x, Comp comp = {}) {
    if (comp(xmax, x)) {
        xmax = x;
        return true;
    }
    return false;
}

// chmin (更新「される」かもしれない値が前)
template <typename T, typename U, typename Comp = less<>> bool chmin(T &xmin, const U &x, Comp comp = {}) {
    if (comp(x, xmin)) {
        xmin = x;
        return true;
    }
    return false;
}

// ローカル用
#ifndef ONLINE_JUDGE
#define DEBUG_
#endif

#ifndef MYLOCAL
#undef DEBUG_
#endif

#ifdef DEBUG_
#define DEB
#define dump(...)                                                                                                      \
    DUMPOUT << "  " << string(#__VA_ARGS__) << ": "                                                                    \
            << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" << endl                                        \
            << "    ",                                                                                                 \
        dump_func(__VA_ARGS__)
#else
#define DEB if (false)
#define dump(...)
#endif

#define VAR(type, ...)                                                                                                 \
    type __VA_ARGS__;                                                                                                  \
    assert((std::cin >> __VA_ARGS__));

template <typename T> istream &operator,(istream &is, T &rhs) { return is >> rhs; }
template <typename T> ostream &operator,(ostream &os, const T &rhs) { return os << ' ' << rhs; }

struct AtCoderInitialize {
    static constexpr int IOS_PREC = 15;
    static constexpr bool AUTOFLUSH = false;
    AtCoderInitialize() {
        ios_base::sync_with_stdio(false), std::cin.tie(nullptr), std::cout.tie(nullptr);
        std::cout << fixed << setprecision(IOS_PREC);
        if (AUTOFLUSH) std::cout << unitbuf;
    }
} ATCODER_INITIALIZE;

void Yn(bool p) { std::cout << (p ? "Yes" : "No") << endl; }
void YN(bool p) { std::cout << (p ? "YES" : "NO") << endl; }

template <typename T> constexpr void operator--(vc<T> &v, int) noexcept {
    for (int i = 0; i < ISIZE(v); ++i) v[i]--;
}
template <typename T> constexpr void operator++(vc<T> &v, int) noexcept {
    for (int i = 0; i < ISIZE(v); ++i) v[i]++;
}

/* #endregion */

// #include <atcoder/all>
// using namespace atcoder;

constexpr int N = 45;
constexpr ll TARGET = 5'00'000'000'000'000'000;

/* #region Timer */

#include <chrono>

struct Timer {
    using clk = chrono::system_clock;

    clk::time_point start_time;
    int64_t timespan_microsecs;
    int64_t elapsed_microsecs;

    // コンストラクタ
    Timer(int64_t timespan_microsecs)
        : start_time(clk::now()), timespan_microsecs(timespan_microsecs), elapsed_microsecs(0) {}

    // 時間切れかどうかを返す
    inline bool is_runnable() noexcept {
        clk::time_point cur_time = clk::now();
        elapsed_microsecs = chrono::duration_cast<chrono::microseconds>(cur_time - start_time).count();
        return elapsed_microsecs < timespan_microsecs;
    }
};

/* #endregion */

/* #region State */

struct State {
    vc<short> history;
    array<ll, N> a; // 表
    array<ll, N> b; // 裏
    ll score;       // 差の絶対値のうち大きい方が loss
    short zero_cnt;
    State(const array<ll, N> &a, const array<ll, N> &b)
        : history(0), a(a), b(b), score(-max(abs(a[0] - TARGET), abs(b[0] - TARGET))), zero_cnt(0) {
        subtract_dist();
    }
    bool operator<(const State &another) const noexcept { return score < another.score; }
    bool operator>(const State &another) const noexcept { return score > another.score; }
    bool operator==(const State &another) const noexcept { return history == another.history; }
    friend ostream &operator<<(ostream &os, const State &x) noexcept {
        os << "[State score=" << x.score << ", history={";
        for (auto const h : x.history) os << h << ", ";
        os << "}]";
        return os;
    }

    void subtract_dist() {
        ll sum = 0;
        TREP(int, i, 1, N) {
            sum += abs(a[i] - TARGET);
            sum += abs(b[i] - TARGET);
        }
        score -= sum / (N * 20);
    }

    void add_history(const short x) noexcept {
        history.push_back(x);
        const short idx0 = x / 100;
        const short idx1 = x % 100;
        ll aval = (a[idx0] + a[idx1]) / 2;
        ll bval = (b[idx0] + b[idx1]) / 2;
        a[idx0] = aval;
        a[idx1] = aval;
        b[idx0] = bval;
        b[idx1] = bval;
        if (idx0 == 0 || idx1 == 0) {
            score = -max(abs(a[0] - TARGET), abs(b[0] - TARGET));
            subtract_dist();
            zero_cnt++;
        }
    }

    void print_history() const {
        pprint(SIZE(history));
        for (const short &x : history) {
            const short idx0 = x / 100;
            const short idx1 = x % 100;
            pprint(idx0 + 1, idx1 + 1);
        }
    }
};

/* #endregion */

/* #region hash */

template <class T> inline void hash_combine(std::size_t &s, const T &v) {
    std::hash<T> h;
    s ^= h(v) + 0x9e3779b9 + (s << 6) + (s >> 2);
}
namespace std {
template <> struct hash<State> {
    std::size_t operator()(const State &state) const {
        std::size_t result = 0;
        for (auto const h : state.history) hash_combine(result, h);
        hash_combine(result, state.score);
        return result;
    }
};
} // namespace std

/* #endregion */

/* #region ChokudaiSearch */

// chokudaiサーチ
// 時間管理もここで行う！
State chokudai_search(int T, State first_state, Timer timer) noexcept {
    vc<pq<State>> vpq_states(T + 1);
    vc<us<State>> vus_states(T + 1); // ターンごとに重複管理する場合
    vpq_states[0].push(first_state); // 0 手目に first_state を入れる
    vus_states[0].insert(first_state);

    int choku = 10; // chokudai幅
    int save = 100; // queueに残す状態の数

    State best_state = first_state;

    int cnt = 0;
    while (timer.is_runnable()) { // 時間いっぱいまで探索する
        cnt++;
        REP(turn, 0, T) { // T ターン分まわす
            {
                // turn 手目の状態群から save 個まで残して、あとは捨てる
                pq<State> pq_tmp;
                REP(i, 0, save) {
                    if (SIZE(vpq_states[turn]) == 0) break;
                    pq_tmp.push(vpq_states[turn].top());
                    vpq_states[turn].pop();
                }
                vpq_states[turn] = move(pq_tmp);
            }
            // turn 手目の状態群から choku 個取り出して遷移をとる
            REP(i, 0, choku) {
                if (SIZE(vpq_states[turn]) == 0) break; // queue が空なら次のターンに

                const State &cur_state = vpq_states[turn].top(); // vpq_states[turn] から1個とる

                // cur_state の近傍をとって vpq_states[turn+1] に入れていく
                TREP(short, idx0, 0, N - 1) TREP(short, idx1, idx0 + 1, N) {
                    const short k = idx0 * 100 + idx1;
                    State next_state = cur_state;
                    next_state.add_history(k);
                    vpq_states[turn + 1].push(next_state);
                    if (next_state > best_state) {
                        best_state = next_state;
                    }
                }
                vpq_states[turn].pop();
            } // end of chokudai width
            if (not timer.is_runnable()) break;
        }
    }
    // dump(cnt);
    // vpq_states の一番後ろのキューから一番スコアの高いものを抜き出して返す
    // State best_state = vpq_states[T].top();
    return best_state;
}

/* #endregion */

// Problem
void solve() {
    Timer timer(950 * 1000);

    VAR(ll, _n);
    array<ll, N> a, b;
    REP(i, 0, N) cin >> a[i], b[i];

    // // サンプル: score_sum: 14,119,672, score_avg: 282,393.44
    // {
    //     State tmp_state(a, b);
    //     for (int i = 1; i <= N - 1; i++) {
    //         tmp_state.add_history(i);
    //     }
    //     // dump(-(ld)tmp_state.score / TARGET);
    //     // dump(tmp_state.a[0], tmp_state.b[0]);
    //     // tmp_state.print_history();
    //     // return;
    //     if (tmp_state > best_state) {
    //         best_state = tmp_state;
    //     }
    // }

    // score_sum: 25,117,812, score_avg: 502,356.24
    // 50回以内
    // → 最大深さが決まっているので chokudai サーチする？
    State first_state(a, b);
    State best_state = chokudai_search(50, first_state, timer);
    // dump(-(ld)best_state.score / TARGET);

    best_state.print_history();
    // dump(best_state.a[0], best_state.b[0]);
}

// entry point
int main() {
    solve();
    return 0;
}