#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <functional>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
#include <tuple>
using namespace std;
typedef long long LL;
typedef complex<double> CMP;
class TreeDistanceConstruction { public:
vector <int> construct(vector <int> d)
{
map<int, vector<int>> d2i;
for (int i = 0; i < d.size(); ++i)
d2i[d[i]].push_back(i);
const int m = d2i.begin()->first;
const int M = d2i.rbegin()->first;
vector<int> ans;
if (d2i[m].size() >= 3)
return vector<int>();
int L = d2i[m].front(), R = d2i[m].back();
if (d2i[m].size() == 1) {
if (2 * m != M)
return vector<int>();
}
else { // d2i[m].size() == 2
if (2*m-1 != M)
return vector<int>();
ans.push_back(L);
ans.push_back(R);
}
for (int k = m + 1; k <= M; ++k) {
if (d2i[k].size() < 2)
return vector<int>();
for (int i = 0; i < d2i[k].size(); ++i) {
ans.push_back(i == 0 ? L : R);
ans.push_back(d2i[k][i]);
}
L = d2i[k].front();
R = d2i[k].back();
}
return ans;
}
};
// BEGIN CUT HERE
#include <ctime>
double start_time; string timer()
{ ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
{ os << "{ ";
for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
void verify_case(const vector <int>& Expected, const vector <int>& Received) {
bool ok = (Expected == Received);
if(ok) cerr << "PASSED" << timer() << endl; else { cerr << "FAILED" << timer() << endl;
cerr << "\to: " << Expected << endl << "\tx: " << Received << endl; } }
#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
#define END verify_case(_, TreeDistanceConstruction().construct(d));}
int main(){
CASE(0)
int d_[] = {3,2,2,3};
vector <int> d(d_, d_+sizeof(d_)/sizeof(*d_));
int __[] = {1, 2, 1, 0, 2, 3 };
vector <int> _(__, __+sizeof(__)/sizeof(*__));
END
CASE(1)
int d_[] = {1,2,2,2};
vector <int> d(d_, d_+sizeof(d_)/sizeof(*d_));
int __[] = {0, 1, 0, 2, 0, 3 };
vector <int> _(__, __+sizeof(__)/sizeof(*__));
END
CASE(2)
int d_[] = {1,1,1,1};
vector <int> d(d_, d_+sizeof(d_)/sizeof(*d_));
vector <int> _;
END
CASE(3)
int d_[] = {1,1,1};
vector <int> d(d_, d_+sizeof(d_)/sizeof(*d_));
vector <int> _;
END
CASE(4)
int d_[] = {1,1};
vector <int> d(d_, d_+sizeof(d_)/sizeof(*d_));
int __[] = {0, 1 };
vector <int> _(__, __+sizeof(__)/sizeof(*__));
END
CASE(5)
int d_[] = { 2,2,3,3,3 };
vector <int> d(d_, d_+sizeof(d_)/sizeof(*d_));
int __[] = { -1 };
vector <int> _(__, __+sizeof(__)/sizeof(*__));
END
CASE(6)
int d_[] = { 3,4,4,5,6,6 };
vector <int> d(d_, d_+sizeof(d_)/sizeof(*d_));
int __[] = { -1 };
vector <int> _(__, __+sizeof(__)/sizeof(*__));
END
}
// END CUT HERE