#include<bits/stdc++.h>
using namespace std;
//#define int long long
//#include<ext/pb_ds/assoc_container.hpp>
//#include<ext/pb_ds/tree_policy.hpp>
//
// #pragma GCC optimize("-O3")
// #pragma GCC optimize("no-stack-protector")
// #pragma GCC optimize("fast-math")
// #pragma GCC optimize("Ofast")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx")
// #pragma GCC target("avx,avx2,fma")
// #pragma GCC optimization ("unroll-loops")
//#define LOCAL
#define sim template < class c
#define ris return * this
#define dor > debug & operator <<
#define eni(x) sim > typename \
enable_if<sizeof dud<c>(0) x 1, debug&>::type operator<<(c i) {
sim > struct rge { c b, e; };
sim > rge<c> range(c i, c j) { return rge<c>{i, j}; }
sim > auto dud(c* x) -> decltype(cerr << *x, 0);
sim > char dud(...);
struct debug {
#ifndef LOCAL
~debug() { cerr << endl; }
eni(!=) cerr << boolalpha << i; ris; }
eni(==) ris << range(begin(i), end(i)); }
sim, class b dor(pair < b, c > d) {
ris << "(" << d.first << ", " << d.second << ")";
}
sim dor(rge<c> d) {
*this << "[";
for (auto it = d.b; it != d.e; ++it)
*this << ", " + 2 * (it == d.b) << *it;
ris << "]";
}
#else
sim dor(const c&) { ris; }
#endif
};
#define imie(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define fi first
#define f first
#define se second
#define vec vector
#define s second
#define vi_a vector<int>a;
#define p_b push_back
#define pb push_back
////////////////////////////////???????????????CHECK THIS OUT???????????????//////////////////////////////
#define ll long long
//#define int long long
typedef unsigned long long ull;
////////////////////////////////???????????????CHECK THIS OUT???????????????//////////////////////////////
#define ld long double
#define pll pair<ll,ll>
#define pii pair<int,int>
#define m_p make_pair
#define fast_io cin.tie(0);cout.tie(0);ios_base::sync_with_stdio(0);
#define all(x) x.begin(),x.end()
#define getfiles ifstream cin("input.txt");ofstream cout("output.txt");
#define pw(x) (1ll << x)
#define sz(x) (int)x.size()
#define endl "\n"
#define rall(x) x.rbegin(),x.rend()
#define len(a) (ll)a.size()
#define rep(x,l,r) for(ll x=l;x<r;x++)
//using namespace __gnu_pbds;
ld eps = (ld)1 / 1e6;
const ld pi=3.14159265359;
ll inf = 1e18,mod1=1e9+7;
ll sqr(ll a) { return a * a; }
ll qb(ll a) { return a * a * a; }
template<typename T> bool umax(T& a, T b) {return a<b?a=b,1:0;}
template<typename T> bool umin(T& a, T b) {return b<a?a=b,1:0;}
bool is_prime(ll val){for(ll i=2;i<=sqrt(val);i++)if(val%i==0)return 0; return 1;}
ll gcd(ll a, ll b) { return !a ? b : gcd(b % a, a); }
ll binpow(ll a, ll b, ll mod) { return b ? (b % 2 ? (a * (sqr(binpow(a, b / 2, mod)) % mod)) % mod : sqr(binpow(a, b / 2, mod)) % mod) : 1; }ll binmult(ll a, ll b, ll mod) { return b ? (b % 2 ? (2 * binmult(a, b / 2, mod) + a) % mod : (2 * binmult(a, b / 2, mod)) % mod) : 0; }
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const ll RR=1e4;
const ll tx[8]={1,-1,2,-2,-1,-2};
const ll ty[8]={-2,-2,-1,-1,2,1};
const char rev_to[4]={'E','W','N','S'};
const int M=1e9+7;
const int N=3e2+3;
const int ppp=73;
const int K=2e5+2;
const int block=600;
const int OPEN=1;
const int CLOSE=0;
//typedef pair<long long,int> pli;
//typedef tree<pli,null_type,less<pli>,rb_tree_tag,tree_order_statistics_node_update> o_st;
auto rnd=bind(uniform_int_distribution<int>(1,5969699),mt19937(time(0)));
void bad(){
cout<<"IMPOSSIBLE";
exit(0);
}
vec<int>a;
int n;
void prnt(vec<int> a,vec<int>b){
cout<<sz(a)<<endl;
for(auto &z : a) cout<<z<<' ';
cout<<endl;
cout<<sz(b)<<endl;
for(auto &z : b) cout<<z<<' ';
exit(0);
}
bool is(const vec<int> &a){
if(sz(a)==1)
return 1;
if(sz(a)==0)
return 0;
int d=a[1]-a[0];
for(int i=2;i<sz(a);i++){
if((a[i]-a[i-1])!=d)
return 0;
}
return 1;
}
bool testcase(int d1){
vec<int>f,s;
f.p_b(a[0]);
// debug()<<imie(d1);
bool ok=1;
for(int i=1;i<n;i++){
if(a[i]-f.back()==d1){
f.pb(a[i]);
}
else{
s.pb(a[i]);
}
}
if(is(f) && is(s)){
prnt(f,s);
}
else{
int l=lower_bound(all(s),f.back())-s.begin();
int vl=f.back();
f.pop_back();
s.insert(s.begin()+l,1,vl);
if(is(f) && is(s)){
prnt(f,s);
}
}
}
signed main()
{
fast_io;
///first is a[0]
// int n;
cin>>n;
a.resize(n);
for(int i=0;i<n;i++){
cin>>a[i];
if(i)
a[i]=a[i]-a[0];
}
a[0]=0;
if(n==2){
cout<<1<<endl;
cout<<a[0]<<endl;
cout<<1<<endl;
cout<<a[1]<<endl;
exit(0);
}
// debug()<<imie(a);
sort(all(a));
// debug()<<imie(a);
vec<int>mp;
for(int i=1;i<n;i++){
mp.pb(a[i]-a[i-1]);
}
sort(all(mp));
// if(sz(mp)>4){
// cout<<-1;
// exit(0);
// }
for(int i=sz(mp)-1;i>=max(sz(mp)-100,0);i--){
testcase(mp[i]);
}
cout<<-1;
return 0;
}
/*
14
0 6583 13166 19749 26332 32915 32949 39498 39535 46081 46121 52664 52707 59247
*/
