#include <fstream>
#include <queue>

using namespace std;

#define MAXN 1000100

typedef pair<long long, int> tp;

struct NOD {
    long long v;
    int fs, fd;
} nod[2 * MAXN];

int n, i, k, a[MAXN];
long long b[MAXN], lt;
int l[MAXN];
pair<long long, int> p;
priority_queue<tp> q;
ifstream fi("huffman.in");
ofstream fo("huffman.out");

void walk_tree(int poz, long long cod, int nivel) {
    if (nod[poz].fs != 0) {
        walk_tree(nod[poz].fs, cod * 2, nivel + 1);
        walk_tree(nod[poz].fd, cod * 2 + 1, nivel + 1);
    }
    else {
        l[poz] = nivel;
        b[poz] = cod;
    }
}

void build_tree() {
    k = n;
    while (q.size() >= 2) {
        k++;
        p = q.top();
        nod[k].fs = p.second;
        nod[k].v += (-p.first);
        q.pop();
        p = q.top();
        nod[k].fd = p.second;
        nod[k].v += (-p.first);
        q.pop();
		lt += nod[k].v;
        q.push(make_pair(-nod[k].v, k));
    }
}

int main() {
    ifstream fi("huffman.in");
    ofstream fo("huffman.out");
    fi >> n;
    for (i = 1; i <= n; i++) {
        fi >> nod[i].v;
        q.push(make_pair(-(nod[i].v), i));
    }
    build_tree();
    walk_tree(k, 0, 0);
    fo << lt << '\n';
    for (i = 1; i <= n; i++)
        fo << l[i] << ' ' << b[i] << '\n';
    return 0;
}