#include <iostream>
#include <fstream>
#include <vector>
#include <list>
#include <utility>
#include <algorithm>
using namespace std;

int main()
{
    int n, s=0;
    ifstream fin("Lab3.in");
    if(fin.is_open())
    {
        fin>>n;
        vector<int> d(n);
        for(int i=0; i<n; i++)
            {
                fin>>d[i];
                s=s+d[i];
                if(d[i]<0) break;
            }
        if(s!=2*(n-1))
            cout<<"Nu se poate construi\n";
        else
        {
            vector<int> tata(n, -1);
            sort(d.begin(), d.end());
            reverse(d.begin(), d.end());
           /* cout<<"verificare";
            for(int i=0; i<n; i++)
                cout<<d[i]<<' ';
                cout<<endl; */
            int big_grad=n-1;
            while(d[big_grad]==1)
            {
                big_grad--;
            }
            int cop=n;
            while(n>=3)
            {
                tata[n-1]=big_grad;
                n--;
                d[big_grad]--;
                if(d[big_grad]==1)
                    big_grad--;
            }
            tata[1]=0;
            for(int i=0;i<cop; i++)
                cout<<tata[i]<<' ';
            n=cop;
            vector<list<int>> lista_fii(n);
            for(int i=1; i<n; i++)
                lista_fii[tata[i]].push_back(i);

        }


    }

    return 0;
}