#include <cstdio>
#include <deque>
using namespace std;
const int NMAX = 1.e6;

struct node{
    long long weight;
    int left, right, pos;
    node(long long _weight = 0, int _left = 0, int _right = 0, int _pos = 0): weight(_weight), left(_left), right(_right), pos(_pos){}
};
node tree[2 * NMAX + 5];

deque <node> dql, dqi;
long long v[NMAX + 5];
int lgc[NMAX + 5], n;
long long lg;

int get_node(){
    if(dql.empty()){
        node ti = dqi.front();
        dqi.pop_front();
        return ti.pos;
    }
    if(dqi.empty()){
        node tl = dql.front();
        dql.pop_front();
        return tl.pos;
    }
    node tl = dql.front();
    node ti = dqi.front();
    if(tl.weight <= ti.weight){
        dql.pop_front();
        return tl.pos;
    }
    else{
        dqi.pop_front();
        return ti.pos;
    }
}

void dfs(int nod, long long val, int lvl){   
    if(nod > n){
        lg += tree[nod].weight;
        dfs(tree[nod].left, val << 1, lvl + 1);
        dfs(tree[nod].right, (val << 1)^1, lvl + 1);
    }
    else{
        v[nod] = val;
        lgc[nod] = lvl;
    }
}

int main(){
    freopen("huffman.in", "r", stdin);
    freopen("huffman.out", "w", stdout);
    int i, free;
    long long w;
    scanf("%d", &n);
    for(i = 1; i <= n; i ++){
        scanf("%lld", &w);
        tree[i].weight = w;
        tree[i].pos = i;
        dql.push_back(tree[i]);
    }
    free = n;
    while(dql.size() + dqi.size() >= 2){
        ++ free;
        tree[free].left = get_node();
        tree[free].right = get_node();
        tree[free].pos = free;
        tree[free].weight = tree[tree[free].left].weight + tree[tree[free].right].weight;
        dqi.push_back(tree[free]);
    }
    dfs(free, 0, 0);
    printf("%lld\n", lg);
    for(i = 1; i <= n; i ++)
        printf("%d %lld\n", lgc[i], v[i]);
    return 0;
}