#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main() {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n; cin >> n;
vector<int> a(n);
for (int &x : a) {
cin >> x;
}
sort(a.begin(), a.end());
for (int d : a) {
cout << d << " ";
}
cout << '\n';
vector<int> v;
int i = 0;
while (i < n - 1) {
if (a[i] != a[i + 1]) {
i += 1;
} else {
v.push_back(a[i]);
i += 2;
}
}
for (int t : v) {
cout << t << " ";
}
cout << '\n';
int z = v.size();
if (z < 2) {
cout << -1;
} else {
cout << v[z - 1] << '\n';
int s = v[z - 2] * v[z - 1];
cout << s;
}
}
