#include<fstream>
#include<queue>
using namespace std;

ifstream in("huffman.in");
ofstream out("huffman.out");

int N;

struct Node
{
	int f1, f2;
	long long val;
};

Node arb[3000010];

vector<pair<int, long long>> r;
vector<pair<int, long long>>::iterator it;

int t = 0;
long long sol=0;

struct comparator
{
	bool operator() (const int n1, const int n2)
	{
		return arb[n1].val > arb[n2].val;
	}
};

priority_queue<int,vector<int>,comparator> pq;

void DFS(int i,long long nr,long long e)
{
	if (arb[i].f1 != 0)
	{
		DFS(arb[i].f1,nr+1,e<<1);
		DFS(arb[i].f2,nr+1,(e<<1)|1LL);
	}
	else
	{
		r.push_back(make_pair(nr, e));
		sol += nr*arb[i].val;
	}
}

int main()
{
	in >> N;

	for (int i = 1;i <= N;++i)
	{
		int e;
		in >> e;
		arb[++t].f1 = 0, arb[t].f2 = 0,arb[t].val=e;
		pq.push(t);
	}

	while (pq.size() != 1)
	{
		int e1, e2;
		e1 = pq.top();
		pq.pop();
		e2 = pq.top();
		pq.pop();

		arb[++t].f1 = e1;
		arb[t].f2 = e2;
		arb[t].val = arb[e1].val + arb[e2].val;

		pq.push(t);		
	}
	DFS(pq.top(), 0, 0);
	out << sol<<'\n';

	for (it = r.begin();it != r.end();++it)
		out << (*it).first << " " << (*it).second << '\n';

	return 0;
}