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

struct node
{
	node *left, *right;
	long long count;
	long long idx;
	
	bool operator<(const node &other) const
	{
		return this->count < other.count;
	}

	bool operator>(const node &other) const
	{
		return this->count > other.count;
	}
};

long long n;
priority_queue<node, vector<node>, greater<node> > q;
vector<pair<long long, long long> > res;

long long df(node *n, long long lg, long long cod)
{
	if(n->left == NULL)
	{
		res[n->idx] = make_pair(lg, cod);
		return 0;
	}
	else
		return n->count + df(n->left, lg + 1, cod << 1) + df(n->right, lg + 1, (cod << 1) + 1);
}

int main()
{
	ifstream cin("huffman.in");
	ofstream cout("huffman.out");

	long long x;
	cin >> n;
	res.resize(n);
	for(long long i=0;i<n;++i)
	{
		cin >> x;
		node n;
		n.right = n.left = NULL;
		n.count = x;
		n.idx = i;
		q.push(n);
	}

	long long count = 0;
	while(q.size() > 1)
	{
		node *s = new node; *s = q.top(); q.pop();
		node *d = new node; *d= q.top(); q.pop();
		node n;
		n.count = s->count + d->count;
		n.left = s;
		n.right = d;
		q.push(n);
	}

	node r = q.top();

	cout << df(&r, 0, 0) << endl;

	for(long long i=0;i<n;++i)
		cout << res[i].first << " " << res[i].second << "\n";

	return 0;
}