#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define all(a) (a).begin(), (a).end()
//#pragma GCC optimize("O3")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define sz() size()
#define fr first
#define sc second
#define pi pair<int,int>
#define pii pair<pair<int,int>,int>
#define mp make_pair
//#define int long long
#define rc(s) return cout<<s,0
#define rcc(s) cout<<s,exit(0)
using namespace std;

const int mod=1e9+7;
const int modp=1999999973;
const int modulo=998244353;

int n;
long long ans;
vector<pair<int,long long>>rs(1000005);
queue<int>tz1,tz2;

struct n{
    long val;
    int f[2];
    n(){
        val=0;
        f[0]=f[1]=0;
    }
}nod[2000005];

void DFS(int s,int cod,int niv){
    if(nod[s].f[0]>=1){
        if(nod[s].f[0]) DFS(nod[s].f[0],2*cod,niv+1);
        if(nod[s].f[1]) DFS(nod[s].f[1],2*cod+1,niv+1);
        return;
    }
    rs[s].fr=niv;
    rs[s].sc=cod;
    return;
}

void solve(){
    int k=n;
    while((tz1.size()+tz2.size())>=2LL){
        k++;
        for(int i=1;i<=2;i++){
            int nod1=1e18;
            if(tz1.size() && tz2.size()){
                if(nod[tz1.front()].val<nod[tz2.front()].val){
                    nod1=tz1.front();
                    tz1.pop();
                }
                else{
                    nod1=tz2.front();
                    tz2.pop();
                }
            }
            else{
                if(tz1.size()){
                    nod1=tz1.front();
                    tz1.pop();
                }
                else{
                    nod1=tz2.front();
                    tz2.pop();
                }
            }
            nod[k].val+=nod[nod1].val;
            nod[k].f[i-1]=nod1;
        }
        ans+=nod[k].val;
        tz2.push(k);
    }
    DFS(k,0,0);
}


int32_t main(){
   // ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
    srand(chrono::steady_clock::now().time_since_epoch().count());
    ifstream cin("huffman.in");
    ofstream cout("huffman.out");
    cin >> n;
    for(int i=1;i<=n;i++){
        cin >> nod[i].val;
        tz1.push(i);
    }
    solve();
    cout << ans << '\n';
    for(int i=1;i<=n;i++) cout << rs[i].fr << ' ' << rs[i].sc << '\n';
}