#include<bits/stdc++.h>
using namespace std;
deque<pair<int,int> > q,q2;
vector<pair<int,pair<int,long long> > > sol;
const int maxN=(1e6)+5;
bool cmp(pair<int,pair<int,int> > a,pair<int,pair<int,int> > b)
{
return a.second.second<b.second.second;
}
int g[maxN][2],n;
int frecv[maxN];
void dfs(int node,int len,long long code)
{
if(node<=n)
{
sol.push_back(make_pair(node,make_pair(len,code)));
return;
}
dfs(g[node-n][0],len+1,code*2LL);
dfs(g[node-n][1],len+1,code*2LL+1LL);
}
char buff[100005];
const int dim=(1e5);
int pos=0;
void read(int &nr)
{
nr=0;
while(!isdigit(buff[pos]))
{
pos++;
if(pos==dim)
{
pos=0;
fread(buff,1,dim,stdin);
}
}
while(isdigit(buff[pos]))
{
nr=nr*10+buff[pos]-'0';
pos++;
if(pos==dim)
{
pos=0;
fread(buff,1,dim,stdin);
}
}
}
int main()
{
freopen("huffman.in","r",stdin);
freopen("huffman.out","w",stdout);
fread(buff,1,dim,stdin);
read(n);
for(int i=1;i<=n;i++)
{
int x;
//scanf("%d",&x);
read(x);
frecv[i]=x;
q.push_back(make_pair(i,x));
}
int currentNode=n;
while(1)
{
vector<pair<int,pair<int,int> >> vect; //for the current Minimum
int cnt=0;
while(!q.empty() && cnt<2)
{
vect.push_back(make_pair(1,q.front()));
q.pop_front();
cnt++;
}
cnt=0;
while(!q2.empty() && cnt<2)
{
vect.push_back(make_pair(2,q2.front()));
q2.pop_front();
cnt++;
}
reverse(vect.begin(),vect.end());
for(auto it:vect)
if(it.first==1) q.push_front(it.second);
else q2.push_front(it.second);
reverse(vect.begin(),vect.end());
if((int)vect.size()<2)
break;
stable_sort(vect.begin(),vect.end(),cmp);
pair<int,pair<int,int> > pr1=vect[0];
pair<int,pair<int,int> > pr2=vect[1];
if(pr1.first==1) q.pop_front();
else q2.pop_front();
if(pr2.first==1) q.pop_front();
else q2.pop_front();
currentNode++;
g[currentNode-n][0]=pr1.second.first;
g[currentNode-n][1]=pr2.second.first;
q2.push_back(make_pair(currentNode,pr1.second.second+pr2.second.second));
}
//printf("%d\n",g[11].size());
//return 0;
dfs(currentNode,0,0);
sort(sol.begin(),sol.end());
long long ans=0;
for(auto it:sol)
{
// printf("%d %d\n",it.second.first,it.second.second);
ans=ans+1LL*frecv[it.first]*it.second.first;
}
printf("%lld\n",ans);
for(auto it:sol)
{
printf("%d %lld\n",it.second.first,it.second.second);
}
return 0;
}