#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 ull=unsigned long long;
using ld=long double;
constexpr int INF=1e9;
constexpr ll INF_ll=1e18;
#define rep(i,n) for (int i=0;i<(int)(n);i++)
#define replr(i,l,r) for (int i=(int)(l);i<(int)(r);i++)
#define all(v) v.begin(),v.end()
#define len(v) ((int)v.size())
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;
}

template<class T> inline bool chmin_ref(T &a,const T &b){
    if(a>b){
        a=b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax_ref(T &a,const T &b){
    if(a<b){
        a=b;
        return true;
    }
    return false;
}

namespace Timer{
    chrono::steady_clock::time_point program_start,start;
    void program_start_snap(){
        program_start=start=chrono::steady_clock::now();
    }
    void snap(){
        start=chrono::steady_clock::now();
    }
    int get_ms(){
        auto now=chrono::steady_clock::now();
        int ms=chrono::duration_cast<chrono::milliseconds>(now-start).count();
        return ms;
    }
    int get_ms_all_program(){
        auto now=chrono::steady_clock::now();
        int ms=chrono::duration_cast<chrono::milliseconds>(now-program_start).count();
        return ms;
    }
}

mt19937 mt;
uint32_t rand_int(uint32_t r){  //[0,r)
    assert(r!=0);
    return ((uint64_t)mt()*r)>>32;
}
int rand_int(int l,int r){  //[l,r)
    assert(l<r);
    return l+rand_int(r-l);
}
constexpr double one_div_mt_max=1.0/(double)mt19937::max();
double rand_double(){  //[0.0,1.0]
    return mt()*one_div_mt_max;
}
double rand_double(double l,double r){  //[l,r]
    return l+rand_double()*(r-l);
}
template<class T> T get_random_element(const vector<T> &v){
    assert(!v.empty());
    return v[rand_int(len(v))];
}

template<class T> void add(vector<T> &a,vector<T> b){
    for(auto i:b) a.push_back(i);
}

template<class SA_State> SA_State SA(const SA_State &first_state,int limit_ms,double start_temp,double end_temp=0.0){

    SA_State state=first_state,best_state=state;
    

    
    int loop_cnt=0,accept_cnt=0,update_cnt=0;
    
    int ms=0;
    
    double temp=start_temp;
    
    Timer::snap();
    
    
    while(true){

        if((loop_cnt&63)==63){
            
            ms=Timer::get_ms();
            
            if(limit_ms<=ms) break;
            
            //double t=(double)ms/limit_ms;
            
            temp=start_temp-(start_temp-end_temp)/limit_ms*ms;
            //temp=pow(start_temp,1-t)*pow(end_temp,t);
            
        }
        
        loop_cnt++;
        
        
        double accept_diff=log(rand_double())*temp;
        

        bool accepted=state.modify(accept_diff);
        
        if(accepted){
            
            accept_cnt++;
        
            if(state.score<best_state.score){
                best_state=state;
                //cerr << "score:" << best_state.score << " ms:" << ms << " loop_cnt:" << loop_cnt << " accept_cnt:" << accept_cnt << " update_cnt:" << update_cnt << '\n';
                update_cnt++;
            }
        }
    }

    
    //cerr << "[result] " << "score:" << best_state.score << " ms:" << ms << " loop_cnt:" << loop_cnt << " accept_cnt:" << accept_cnt << " update_cnt:" << update_cnt << '\n';
    
    return best_state;
};


constexpr int N=45;

array<ll,N> A,B;

constexpr ll L=5e17,M=1e18;

ll calc_score(const vector<int> &ord){
            
    array<ll,N> a=A,b=B;
    
    for(auto e:ord){
        a[0]=a[e]=(a[0]+a[e])/2;
        b[0]=b[e]=(b[0]+b[e])/2;
    }
    
    return max(abs(L-a[0]),abs(L-b[0]));
}

namespace Solver{
    
    struct State{
        
        vector<int> ord;
        
        double score=0;
        
        State():ord(N-1){
            rep(i,N-1){
                ord[i]=1+i;
            }
            score=calc_score();
        }
        
        double calc_score() const{
            
            return log10(::calc_score(ord)+1);
        }
        
        
        bool modify(double accept_diff){
            
            int a=rand_int(N-1),b=rand_int(N-1);
            
            swap(ord[a],ord[b]);
            
            double new_score=calc_score();
            
            
            if(accept_diff<=score-new_score){
                score=new_score;
                return true;
            }else{
                swap(ord[a],ord[b]);
                return false;
            }
        }
    };
    
    void dfs(int k,ll x,ll y,vector<int> &cand,vector<int> &used,vector<int> &ord,ll &best_score,vector<int> &best_ord){
        
        static int loop=0;
        
        static bool fin=false;
        
        if(fin) return;
        
        loop++;
        
        if((loop&1023)==0){
            if(900<Timer::get_ms()) fin=true;
        }
        
        if(k==-1){
            
            ll now_score=calc_score(ord);
            
            if(chmin(best_score,now_score)){
                best_ord=ord;
            }
            return;
        }
        rep(i,len(cand)){
            if(used[i]) continue;
            
            ll nx=x+(A[cand[i]]>>(N-1-k));
            ll ny=y+(B[cand[i]]>>(N-1-k));
            
            if(10000<nx-L) continue;
            if(nx+(M>>(N-1-k))-L<-10000) continue;
            if(10000<ny-L) continue;
            if(ny+(M>>(N-1-k))-L<-10000) continue;
            
            
            used[i]=true;
            ord[k]=cand[i];
            dfs(k-1,nx,ny,cand,used,ord,best_score,best_ord);
            ord[k]=-1;
            used[i]=false;
        }
    }
    
    
    void solve(){
        State state;
        state=SA<State>(state,100,0.2,0.2);
        
        vector<int> ord=state.ord;
        
        ll best_score=calc_score(ord);
        
        vector<int> best_ord=ord;
        
        replr(s,1,N-1){
            
            ll x=0,y=0;
            
            replr(i,s,N-1){
                x+=A[ord[i]]>>(N-1-i);
                y+=B[ord[i]]>>(N-1-i);
            }
            
            vector<int> cand;
            
            vector<int> now_ord=ord;
            
            rep(i,s){
                cand.push_back(ord[i]);
                now_ord[i]=-1;
            }
            
            vector<int> used(len(cand),false);
            
            dfs(s-1,x,y,cand,used,now_ord,best_score,best_ord);
        }
        
        
        cout << len(best_ord) << '\n';
        
        for(auto e:best_ord){
            cout << 1 << ' ' << e+1 << '\n';
        }
        
        
        cerr << (int)floor(2000000-100000*log10(best_score+1)) << ' ' << Timer::get_ms() << '\n';
        
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    Timer::program_start_snap();
    
    int n;
    cin >> n;
    assert(n==N);
    
    rep(i,N) cin >> A[i] >> B[i];


    Solver::solve();
    exit(0);
}