// May this submission get accepted!

#pragma GCC optimize ("O3")
#pragma GCC target ("tune=native")
#pragma GCC target ("avx")

#include <bits/stdc++.h>

// 汎用マクロ
#define ALL_OF(x) (x).begin(), (x).end()
#define REP(i,n) for (long long i=0, i##_len=(n); i<i##_len; i++)
#define RANGE(i,is,ie) for (long long i=(is), i##_end=(ie); i<=i##_end; i++)
#define DSRNG(i,is,ie) for (long long i=(is), i##_end=(ie); i>=i##_end; i--)
#define STEP(i, is, ie, step) for (long long i=(is), i##_end=(ie), i##_step = (step); i<=i##_end; i+=i##_step)
#define UNIQUE(v) do { sort((v).begin(), (v).end()); (v).erase(unique((v).begin(), (v).end()), (v).end()); } while (false)
template<class T> bool chmax(T &a, const T &b) { if (a < b) {a = b; return true;} return false; }
template<class T> bool chmin(T &a, const T &b) { if (a > b) {a = b; return true;} return false; }
#define INF 0x7FFFFFFF
#define LINF 0x7FFFFFFFFFFFFFFFLL
#define Yes(q) ((q) ? "Yes" : "No")
#define YES(q) ((q) ? "YES" : "NO")
#define Possible(q) ((q) ? "Possible" : "Impossible")
#define POSSIBLE(q) ((q) ? "POSSIBLE" : "IMPOSSIBLE")
#define DUMP(q) cerr << "[DEBUG] " #q ": " << (q) << " at " __FILE__ ":" << __LINE__ << endl
#define DUMPALL(q) do { cerr << "[DEBUG] " #q ": ["; REP(DUMPALL_ITR, (q).size()) { cerr << (q)[DUMPALL_ITR] << (DUMPALL_ITR == DUMPALL_ITR_len-1 ? "" : ", "); } cerr << "] at " __FILE__ ":" << __LINE__ << endl; } while (false)
template<class T> T gcd(T a, T b) { if (a < b) std::swap(a, b); while (b) std::swap(a %= b, b); return a; }
template<class T> T lcm(const T a, const T b) { return a / gcd(a, b) * b; }

// gcc拡張マクロ
#define popcount __builtin_popcount
#define popcountll __builtin_popcountll

// エイリアス
#define DANCE_ long
#define ROBOT_ unsigned
#define HUMAN_ signed
using  ll = DANCE_ HUMAN_ DANCE_;
using ull = DANCE_ ROBOT_ DANCE_;
using  ld = long double;
using namespace std;

// モジュール


// 処理内容
int main() {
    
    // インタラクティブ問題では除去した方がいいかも
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    ll n; cin >> n;
    vector<ll> a(n);
    REP(i, n) cin >> a[i];

    sort(ALL_OF(a));

    vector<pair<ll, ll>> ans; ans.reserve(n-1);
    if(a.size() > 2) {
        auto itr = lower_bound(ALL_OF(a), 0LL);
        vector<ll> aneg(a.begin(), itr);
        vector<ll> apos(itr, a.end());
        if (aneg.empty()) {
            ll x = a[0] - a[1];
            ans.emplace_back(a[0], a[1]);
            RANGE(i, 2, n-2) {
                ans.emplace_back(x, a[i]);
                x -= a[i];
            }
            ans.emplace_back(a[n-1], x);
        } else if (apos.empty()) {
            reverse(ALL_OF(a));
            ll x = a[0] - a[1];
            ans.emplace_back(a[0], a[1]);
            RANGE(i, 2, n-1) {
                ans.emplace_back(x, a[i]);
                x -= a[i];
            }
        } else {
            while(aneg.size() > 1) {
                ll x = apos.back() - aneg.back();
                ans.emplace_back(apos.back(), aneg.back());
                apos.pop_back();
                aneg.pop_back();
                apos.push_back(x);
            }
            while (apos.size() > 1) {
                ll x = aneg.back() - apos.back();
                ans.emplace_back(aneg.back(), apos.back());
                apos.pop_back();
                aneg.pop_back();
                aneg.push_back(x);
            }
            ans.emplace_back(apos.back(), aneg.back());
        }
    } else {
        ll mx = max(a[0], a[1]);
        ll mn = min(a[0], a[1]);
        ans.emplace_back(mx, mn);
    }

    cout << ans.back().first - ans.back().second << endl;
    REP(i, ans.size()) {
        cout << ans[i].first << " " << ans[i].second << endl;
    }
    
}

Measured memory_bytes: 4276