#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/tag_and_trait.hpp>
#include <ext/pb_ds/trie_policy.hpp>

using namespace __gnu_pbds;
using namespace std;

#define rep(i,n) for(int i=0;i<(n);++i)
#define reps(i,n) for(int i=1;i<=(n);++i)
#define all(x) begin(x),end(x)
#define Fixed fixed << setprecision(12)
#define int int_fast64_t
using pii = pair<int,int>;
constexpr int INF  = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr int mod1 = 1e9+7;
constexpr int mod2 = 998244353;

template <class Func>
class FixPoint : Func {
public:
    explicit constexpr FixPoint(Func&& f) noexcept : Func(forward<Func>(f)) {}

    template <class... Args>
    constexpr decltype(auto) operator()(Args&&... args) const {
        return Func::operator()(*this, std::forward<Args>(args)...);
    }
};

template <class Func>
static inline constexpr decltype(auto) makeFixPoint(Func&& f) noexcept {
    return FixPoint<Func>{forward<Func>(f)};
}

template <class A, class B> inline bool chmax(A &a, const B &b) { return b > a && (a = b, true); }
template <class A, class B> inline bool chmin(A &a, const B &b) { return b < a && (a = b, true); }

template <class T> using min_heap = priority_queue<T,vector<T>,greater<T> >;
template <class T> using max_heap = priority_queue<T>;
template <class A, class B> using umap = unordered_map<A,B>;
template <class T> using Set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <class K, class V> using Umap = gp_hash_table<K, V>;
using Trie = trie<string, null_type, trie_string_access_traits<>, pat_trie_tag, trie_prefix_search_node_update>;

inline int square(int a){ return a * a;}
inline int updiv(int a,int b){ return (a + b - 1) / b; }

constexpr int dx[] = {1,0,-1,0,1,1,-1,-1};
constexpr int dy[] = {0,-1,0,1,1,-1,-1,1};


signed main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout.setf(ios_base::fixed);
    cout.precision(10);

    int n;
    cin >> n;

    deque<int> a(n);

    rep(i,n){
        cin >> a[i];
    }

    vector<int> x, y;

    if(all_of(all(a), [](auto a){ return (a <= 0); })){
        sort(all(a), greater<>());
        x.emplace_back(a[0]);
        y.emplace_back(a[1]);
        a[1] = a[0] - a[1];
        a.pop_front();
        sort(all(a), greater<>());
        while(a.size() > 1){
            x.emplace_back(a[0]);
            y.emplace_back(a[1]);
            a[1] = a[0] - a[1];
            a.pop_front(); 
        }
    }else if(all_of(all(a), [](auto a){ return (a > 0); })){
        sort(all(a));
        if(a.size() == 2){
            cout << a[1] - a[0] << '\n';
            cout << a[1] << ' ' << a[0] << '\n';
            return (0);
        }
        x.emplace_back(a[0]);
        y.emplace_back(a[1]);
        a[1] = a[0] - a[1];
        a.pop_front();
        while(a.size() > 2){
            x.emplace_back(a[0]);
            y.emplace_back(a[1]);
            a[1] = a[0] - a[1];
            a.pop_front();
        }
        x.emplace_back(a[1]);
        y.emplace_back(a[0]);
        a[1] = a[1] - a[0];
        a.pop_front();
    }else{
        sort(all(a));
        while(*next(a.rbegin()) > 0){
            x.emplace_back(a.front());
            y.emplace_back(a.back());
            a.front() = a.front() - a.back();
            a.pop_back();
        }
        reverse(all(a));
        while(a.size() > 1){
            x.emplace_back(a.front());
            y.emplace_back(a.back());
            a.front() = a.front() - a.back();
            a.pop_back();
        }
    }

    cout << a.front() << '\n';
    rep(i,n-1){
        cout << x[i] << ' ' << y[i] << '\n';
    }

    return 0;
}

Measured memory_bytes: 5988