#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, n) for(int i = a; i < n; i++)
#define rrep(i, a, n) for(int i = a; i >= n; i--)
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
constexpr ll MOD = 1000000007;
constexpr int IINF = 1001001001;
constexpr ll INF = 1LL<<60;

template<class t,class u> void chmax(t&a,u b){if(a<b)a=b;}
template<class t,class u> void chmin(t&a,u b){if(b<a)a=b;}

// 問題
// https://yukicoder.me/problems/no/5020


int main(){
    int n; cin >> n;
    vector<tuple<ll, ll, ll>> card(n);
    rep(i, 0, n){
        ll a, b; cin >> a >> b;
        card[i] = {a, b, i+1};
    }
    sort(card.begin(), card.end());
    vector<pair<ll, ll>> ope;
    rep(_, 0, 2){
        rep(__, 0, 25){
            // 1~25回目は表、26~50回目は裏が最大, 最小となるカードについて操作を行う
            auto [a, c, i] = card[0];
            auto [b, d, j] = card[n-1];
            card[0] = {(a+b)/2, (c+d)/2, i};
            card[n-1] = {(a+b)/2, (c+d)/2, j};
            ope.push_back({i, j});
            sort(card.begin(), card.end());
        }
        rep(i, 0, n){
            auto [a, c, j] = card[i];
            card[i] = {c, a, j};
        }
    }

    // 出力
    cout << ope.size() << endl;
    for(auto [u, v]: ope){
        cout << u << ' ' << v << endl;
    }

    // // スコア
    // ll base = 5e17;
    // rep(i, 0, n){
    //     auto [a, c, j] = card[i];
    //     if(j == 1){
    //         cout << (ll)(2e6-1e5*log10(max(abs(a-base), abs(c-base))+1)) << endl;
    //     }
    // }
    return 0;
}