#include <bits/stdc++.h>
using namespace std;
using pii=pair<int,int>;
using tii=tuple<int,int,int>;
using qii=tuple<int,int,int,int>;
using ll=long long;
using ld=long double;
const ll INF=1ll<<60;
#define rep(i,n) for (int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
template<class T> inline bool chmin(T &a,T b){
    if(a>b){
        a=b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T &a,T b){
    if(a<b){
        a=b;
        return true;
    }
    return false;
}
auto program_start=chrono::system_clock::now();
mt19937 mt;
int rand_int(int r){    //[0,r)
    return mt()%r;
}
int rand_int(int l,int r){  //[l,r)
    return l+mt()%(r-l);
}
double rand_double(){   //[0.0,1.0]
    return (double)mt()/(double)mt19937::max();
}
const ll C=5e17;
int N;
vector<ll> A,B;
namespace Solver{
    int score(vector<pii> &ans){
        vector<ll> a=A,b=B;
        for(auto [u,v]:ans){
            a[v]=a[u]=(a[u]+a[v])/2;
            b[v]=b[u]=(b[u]+b[v])/2;
        }
        return floorl(2000000.0-100000.0*log10l(max(abs(C-a[0]),abs(C-b[0]))+1));
    }
    void solve(){
        vector<ll> a=A,b=B;
        vector<pii> ans;
        while((int)ans.size()<50){
            ll mn=INF;
            int idx=-1;
            for(int i=1;i<N;i++){
                ll x=abs(C-(a[0]+a[i])/2),y=abs(C-(b[0]+b[i])/2);
                if(chmin(mn,x+y)) idx=i;
            }
            ll pre_score=abs(C-a[0])+abs(C-b[0]);
            a[0]=(a[0]+a[idx])/2;
            a[idx]=a[0];
            b[0]=(b[0]+b[idx])/2;
            b[idx]=b[0];
            ll new_score=abs(C-a[0])+abs(C-b[0]);
            if(pre_score<=new_score) break;
            ans.emplace_back(0,idx);
        }
        cout << (int)ans.size() << '\n';
        for(auto [u,v]:ans) cout << u << ' ' << v << '\n';
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> N;
    A.resize(N);
    B.resize(N);
    rep(i,N) cin >> A[i] >> B[i];
    Solver::solve();
}