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

#define code count

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

	node()
	{
		left = right = -1;
	}
};

int n;
vector<node> c;
int st, dr;

void bfs()
{
	int n;
	queue<int> q;
	q.push(c.size() - 1);
	c[c.size() - 1].code = 0;
	c[c.size() - 1].len = 0;

	while(!q.empty())
	{
		n = q.front(); q.pop();
		if(c[n].left == -1)
			continue;
		else
		{
			long long code = c[n].code << 1;
			int l = c[n].left, r = c[n].right;
			c[l].code = code;
			c[r].code = code + 1;
			c[l].len = c[r].len = c[n].len + 1;
			q.push(l);
			q.push(r);
		}
	}
}

inline int pop()
{
	if(st==n)
		return dr ++;
	if(dr==c.size())
		return st ++;
	if(c[st].count <= c[dr].count)
		return st ++;
	return dr++;
}

char buf[1000000];

int main()
{
	ifstream cin("huffman.in");
	cin.rdbuf()->pubsetbuf(buf, sizeof(buf));
	ofstream cout("huffman.out");
	c.reserve(2000000);

	int x;
	cin >> n;
	c.resize(n);
	for(int i=0;i<n;++i)
	{
		cin >> x;
		c[i].right = c[i].left = -1;
		c[i].count = x;
	}
	st = 0; dr = n;

	long long count = 0;
	int s, d;
	while((n-st+c.size()-dr) > 1)
	{
		s = pop();
		d = pop();
		c.push_back(node());
		node &n = c[c.size() - 1];
		n.count = c[s].count + c[d].count;
		count += n.count;
		n.left = s;
		n.right = d;
	}

	bfs();

	cout << count << endl;

	for(int i=0;i<n;++i)
		cout << c[i].len << " " << c[i].code << "\n";

	return 0;
}