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

#define code count

struct node
{
	node *left, *right;
	long long count;
	short len;

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

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

int n;
vector<node*> res;
deque<node *> a, b;

void bfs(node *n)
{
	queue<node*> q;
	q.push(n);
	n->code = 0;
	n->len = 0;

	while(!q.empty())
	{
		n = q.front(); q.pop();
		if(n->left == NULL)
			continue;
		else
		{
			long long code = n->code << 1;
			n->left->code = code;
			n->right->code = code + 1;
			n->left->len = n->right->len = n->len + 1;
			q.push(n->left);
			q.push(n->right);
		}
	}
}

inline node* pop(deque<node*> &a)
{
	node *tmp = a[0];
	a.pop_front();
	return tmp;
}

inline node* pop()
{
	if(a.size() == 0)
		return pop(b);
	if(b.size() == 0)
		return pop(a);
	if(a[0]->count <= b[0]->count)
		return pop(a);
	return pop(b);
}

char buf[1000000];

int main()
{
	ifstream cin("huffman.in");
	cin.rdbuf()->pubsetbuf(buf, sizeof(buf));
	ofstream cout("huffman.out");

	long long x;
	cin >> n;
	res.resize(n);
	a.resize(n);
	for(int i=0;i<n;++i)
	{
		cin >> x;
		node *n = new node;
		n->right = n->left = NULL;
		n->count = x;
		res[i] = a[i] = n;
	}

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

	node *r = pop();
	bfs(r);

	cout << count << endl;

	for(int i=0;i<n;++i)
		cout << res[i]->len << " " << res[i]->code << "\n";

	return 0;
}