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

const int MAX_N = 1000002;
const int SIGMA = 2;

struct Node {
    int ind;
    int sons[SIGMA];
    long long val;

    Node() {
        val = ind = 0;
        for(int i = 0; i < SIGMA; ++i)
            sons[i] = 0;
    }
};

int N;
int frequency[MAX_N];
long long ans;
pair < int, long long > sol[MAX_N];
Node v[2 * MAX_N];
deque < Node > a, b;

void DFS(Node node, long long code, int lv) {
    for(size_t i = 0; i < SIGMA; ++i)
        if(node.sons[i])
            DFS(v[node.sons[i]], code * 2 + i, lv + 1);
    if(node.ind <= N) {
        sol[node.ind] = make_pair(lv, code);
        ans += (long long) lv * frequency[node.ind];
    }
}

Node getMin() {
    Node ret;

    if(a.empty()) {
        ret = b.back();
        b.pop_back();
    }
    else if(b.empty()) {
        ret = a.back();
        a.pop_back();
    }
    else if(a.back().val < b.back().val) {
        ret = a.back();
        a.pop_back();
    }
    else {
        ret = b.back();
        b.pop_back();
    }

    return ret;
}

int main() {
    ifstream f("huffman.in");
    ofstream g("huffman.out");

    f >> N;
    Node temp;
    for(int i = 1; i <= N; ++i) {
        f >> frequency[i];

        temp.val = frequency[i];
        temp.ind = i;
        v[i] = temp;
        a.push_front(temp);
    }

    int p = N + 1;
    Node node, temp1, temp2;
    while(!a.empty() || b.size() > 1) {
        temp1 = getMin();
        temp2 = getMin();

        node.val = temp1.val + temp2.val;
        node.ind = p;
        node.sons[0] = temp1.ind, node.sons[1] = temp2.ind;
        v[p] = node;
        ++p;

        b.push_front(node);
    }

    DFS(node, 0, 0);

    g << ans << "\n";
    for(int i = 1; i <= N; ++i)
        g << sol[i].first << " " << sol[i].second << "\n";

    f.close();
    g.close();

    return 0;
}