#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<class T>
using ordered_set = tree<T, null_type, less<T>,
rb_tree_tag, tree_order_statistics_node_update>;
template<class T, class U>
using ordered_map = tree<T, U, less<T>, rb_tree_tag,
tree_order_statistics_node_update>;
#define ll long long
#define ld long double
#define MOD 998244353
#define MAXN 250000
#define SIZE 100
#define pb push_back
ll power(ll a, ll b){
if (b == 0) return 1;
ll res = power(a, b / 2);
// if (b % 2 == 1) return res * res % MOD * a % MOD;
// return res * res % MOD;
if (b % 2 == 1) return res * res * a;
return res * res;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n;
cin >> n;
vector<int> nums(n);
for (int i = 0; i < n; i++){
cin >> nums[i];
}
sort(nums.begin(), nums.end());
vector<int> a, b;
a.pb(nums[0]);
a.pb(nums[1]);
vector<bool> used(n, 0);
used[0] = 1;
used[1] = 1;
for (int i = 2; i < n; i++){
if (nums[i] - a.back() == a[1] - a[0]){
used[i] = 1;
a.pb(nums[i]);
}
}
bool can = 1;
for (int i = 0; i < n; i++){
if (!used[i]){
if (b.size() < 2){
used[i] = 1;
b.pb(nums[i]);
continue;
}
if (nums[i] - b.back() == b[1] - b[0]){
used[i] = 1;
b.pb(nums[i]);
}
else{
can = 0;
break;
}
}
}
if (b.empty()){
b.pb(a.back());
a.pop_back();
}
if (can){
cout << a.size() << "\n";
for (auto &num : a) cout << num << " ";
cout << "\n";
cout << b.size() << "\n";
for (auto &num : b) cout << num << " ";
cout << "\n";
return 0;
}
//N minimum 3 here
can = 1;
a.clear();
b.clear();
for (int i = 0; i < n; i++) used[i] = 0;
a.pb(nums[0]);
b.pb(nums[1]);
a.pb(nums[2]);
used[0] = used[1] = used[2] = 1;
for (int i = 3; i < n; i++){
if (nums[i] - a.back() == a[1] - a[0]){
used[i] = 1;
a.pb(nums[i]);
}
}
for (int i = 0; i < n; i++){
if (!used[i]){
if (b.size() < 2){
used[i] = 1;
b.pb(nums[i]);
continue;
}
if (nums[i] - b.back() == b[1] - b[0]){
used[i] = 1;
b.pb(nums[i]);
}
else{
can = 0;
break;
}
}
}
if (b.empty()){
b.pb(a.back());
a.pop_back();
}
if (can){
cout << a.size() << "\n";
for (auto &num : a) cout << num << " ";
cout << "\n";
cout << b.size() << "\n";
for (auto &num : b) cout << num << " ";
cout << "\n";
return 0;
}
can = 1;
a.clear();
b.clear();
for (int i = 0; i < n; i++) used[i] = 0;
a.pb(nums[0]);
b.pb(nums[1]);
b.pb(nums[2]);
used[0] = used[1] = used[2] = 1;
for (int i = 3; i < n; i++){
if (nums[i] - b.back() == b[1] - b[0]){
used[i] = 1;
b.pb(nums[i]);
}
}
for (int i = 0; i < n; i++){
if (!used[i]){
if (a.size() < 2){
used[i] = 1;
a.pb(nums[i]);
continue;
}
if (nums[i] - a.back() == a[1] - a[0]){
used[i] = 1;
a.pb(nums[i]);
}
else{
can = 0;
break;
}
}
}
if (a.empty()){
a.pb(b.back());
b.pop_back();
}
if (can){
cout << a.size() << "\n";
for (auto &num : a) cout << num << " ";
cout << "\n";
cout << b.size() << "\n";
for (auto &num : b) cout << num << " ";
cout << "\n";
return 0;
}
cout << "-1\n";
return 0;
}
