#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
//#include <Rescue.h>


using namespace std;
//using namespace __gnu_pbds;


#define INF (1<<30)
#define INFll (1ll<<62)
#define F first
#define S second
#define MOD 1000000007
#define mkp(a, b) make_pair(a, b)
#define MAX(a, b) (((a) >= (b)) ? (a) : (b))
#define MIN(a, b) (((a) <= (b)) ? (a) : (b))



typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

#ifndef LOCAL
    #define cerr if(false) cerr
#endif // LOCAL

#define FOR(I, A, B) for(int (I) = (A); (I) < (B); (I)++)
#define ROF(I, A, B) for(int (I) = (A); (I) >= (B); (I)--)
#define SQR(A) 1ll*(A)*(A)


//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;


const char array_sep[] = " ";
const char array_end[] = "";


const char pair_sep[] = " ";
const char pair_end[] = "";


const char map_sep[] = "->";
const char map_end[] = "\n";


const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};
const int ddx[] = {-1, -1, 0, 1, 1, 1, 0, -1};
const int ddy[] = {0, 1, 1, 1, 0, -1, -1, -1};


template<typename A> ostream & operator<<(ostream & os, const vector<A> & x)
{
	for(int i = 0; i < x.size(); i++)
		os << x[i] << array_sep;
	os << array_end;
	return os;
}


template<typename A, typename B> ostream & operator<<(ostream & os, const pair<A, B> & x)
{
	os << x.first << pair_sep << x.second << pair_end;
	return os;
}


template<typename A> istream & operator>>(istream & is, vector<A> & x)
{
	for(int i = 0; i < x.size(); i++)
		is >> x[i];
	return is;
}


template<typename A, typename B> istream & operator>>(istream & is, pair<A, B> & x)
{
	is >> x.first >> x.second;
	return is;
}

//#define cerr if(0)cerr

//
//template<typename _key, typename _val> ostream & operator<<(ostream & os, map<_key, _val> & mp)
//{
//	for(auto it : mp)   // not for C++98 or earlier
//		os << it->F << map_sep << it->S << map_end;
//	return os;
//}
//
//template<typename _key, typename _val> ostream & operator<<(ostream & os, unordered_map<_key, _val> & mp)
//{
//	for(auto it : mp)   // not for C++98 or earlier
//		os << it->F << map_sep << it->S << map_end;
//	return os;
//}
//
//template<typename _key, typename _val> ostream & operator<<(ostream & os, set<_key> & st)
//{
//	for(auto& it: st)   // not for C++98 or earlier
//		os << it << endl;
//	return os;
//}
//
//template<typename _key, typename _val> ostream & operator<<(ostream & os, unordered_set<_key> & st)
//{
//	for(auto& it: st)   // not for C++98 or earlier
//		os << it << endl;
//	return os;
//}

template<typename _response> void die(_response ans)
{
	cout << ans << endl;
	exit(0);
}

int main()
{
#ifdef LOCAL
	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);
//	freopen("errlog.log", "w", stderr);
	ios_base::sync_with_stdio(0);
//	cout << fixed << setprecision(3);
#else // LOCAL
//    freopen("gcd-xor.in", "r", stdin);
//	freopen("gcd-xor.out", "w", stdout);
	ios_base::sync_with_stdio(0);
//	cout << fixed << setprecision(3);
#endif // LOCAL
    int n;
    vector<int> a;
    vector<pair<int, int > > ans;

    cin >> n;
    a.resize(n << 1);
    cin >> a;

    set<pair<pair<int, int >, pair<int, int > > > st;
    vector<int> l_lnk(n << 1, -1);
    vector<int> r_lnk(n << 1, -1);

    sort(a.begin(), a.end());

    for(int i = 0; i < (n << 1); i++)
    {
        if(i) l_lnk[i] = i-1;
        if(i != (n << 1) - 1) r_lnk[i] = i+1;
        if(i) st.insert({{a[i] - a[i-1], -a[i]-a[i-1]}, {i-1, i}});
    }

    while(true)
    {
//        cerr << "# " << i << " " << st.size() << " ";
        if(st.empty()) break;
        auto top = *st.begin(); st.erase(st.begin());
        int l = top.S.F;
        int r = top.S.S;
        cerr << top << endl;
        cerr << "\t#" << l_lnk[l] << " " << r_lnk[r] << endl;
        ans.push_back(mkp(a[top.S.F], a[top.S.S]));


        if(l_lnk[l] == -1 && r_lnk[r] == -1) continue;
        if(l_lnk[l] == -1 && r_lnk[r] != -1)
        {
            l_lnk[r_lnk[r]] = -1;
            st.erase({{a[r_lnk[r]] - a[r], -a[r]-a[r_lnk[r]]}, {r, r_lnk[r]}});
            continue;
        }
        if(l_lnk[l] != -1 && r_lnk[r] == -1)
        {
            r_lnk[l_lnk[l]] = -1;
            st.erase({{a[l] - a[l_lnk[l]], -a[l]-a[l_lnk[l]]}, {l_lnk[l], l}});
            continue;
        }
        if(l_lnk[l] != -1 && r_lnk[r] != -1)
        {
            r_lnk[l_lnk[l]] = r_lnk[r];
            l_lnk[r_lnk[r]] = l_lnk[l];
            st.erase({{a[l] - a[l_lnk[l]], -a[l]-a[l_lnk[l]]}, {l_lnk[l], l}});
            st.erase({{a[r_lnk[r]] - a[r], -a[r]-a[r_lnk[r]]}, {r, r_lnk[r]}});
            st.insert({{a[r_lnk[r]] - a[l_lnk[l]], -a[l_lnk[l]]-a[r_lnk[r]]}, {l_lnk[l], r_lnk[r]}});
            continue;
        }
//        cout << st.size() << endl;
    }

    for(int i = 0; i < n; i++)
        cout << max(ans[i].F, ans[i].S) << " ";
    cout << endl;
    for(int i = 0; i < n; i++)
        cout << min(ans[i].F, ans[i].S) << " ";

 	return 0;
}