#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int, int> pii;
const int MXN = 100005;
int n, a[MXN];
multiset<int> MS;
inline void COUT(vector<int> &L, vector<int> &R) {
cout << L.size() << endl;
for (auto &i : L) cout << i << ' ';
cout << endl << R.size() << endl;
for (auto &i : R) cout << i << ' ';
cout << endl;
}
bool check2(multiset<int> MS) {
int pre = *MS.begin();
MS.erase(MS.begin());
int miku = -1;
for (auto it = MS.begin(); it != MS.end(); it++) {
if (miku == -1) miku = *it - pre;
else if (miku != *it - pre) return false;
pre = *it;
}
return true;
}
bool check(multiset<int> MS, int a0, int d) {
vector<int> L, R;
while (MS.find(a0) != MS.end()) {
L.push_back(a0);
MS.erase(MS.find(a0));
a0 += d;
}
if (MS.empty()) {
R.push_back(L.back());
L.pop_back();
COUT(L, R);
return true;
}
if (check2(MS)) {
for (auto it = MS.begin(); it != MS.end(); it++) R.push_back(*it);
COUT(L, R);
return true;
}
MS.insert(L.back());
L.pop_back();
if (check2(MS)) {
for (auto it = MS.begin(); it != MS.end(); it++) R.push_back(*it);
COUT(L, R);
return true;
}
return false;
}
void solve() {
cin >> n;
for (int i = 0; i < n; i++) cin >> a[i];
sort(a, a + n);
if (n == 2) {
cout << 1 << endl << a[0] << endl << 1 << endl << a[1] << endl;
return;
}
for (int i = 0; i < n; i++) MS.insert(a[i]);
if (check(MS, a[0], a[1] - a[0])) return;
if (check(MS, a[1], a[2] - a[1])) return;
if (check(MS, a[0], a[2] - a[0])) return;
cout << -1 << endl;
}
int32_t main() {
cin.tie(0) -> sync_with_stdio(false);
solve();
return 0;
}
