#pragma GCC optimize("O3")

#include <bits/stdc++.h>

using namespace std;

#define n_l '\n'
#define dbg(...) cout << "[" << #__VA_ARGS__ << "]: "; cout << to_string(__VA_ARGS__) << endl
template <typename T, size_t N> int SIZE(const T (&t)[N]){ return N; } template<typename T> int SIZE(const T &t){ return t.size(); } string to_string(const string s, int x1=0, int x2=1e9){ return '"' + ((x1 < s.size()) ? s.substr(x1, x2-x1+1) : "") + '"'; } string to_string(const char* s) { return to_string((string) s); } string to_string(const bool b) { return (b ? "true" : "false"); } string to_string(const char c){ return string({c}); } template<size_t N> string to_string(const bitset<N> &b, int x1=0, int x2=1e9){ string t = ""; for(int __iii__ = min(x1,SIZE(b)),  __jjj__ = min(x2, SIZE(b)-1); __iii__ <= __jjj__; ++__iii__){ t += b[__iii__] + '0'; } return '"' + t + '"'; } template <typename A, typename... C> string to_string(const A (&v), int x1=0, int x2=1e9, C... coords); int l_v_l_v_l = 0, t_a_b_s = 0; template <typename A, typename B> string to_string(const pair<A, B> &p) { l_v_l_v_l++; string res = "(" + to_string(p.first) + ", " + to_string(p.second) + ")"; l_v_l_v_l--; return res; } template <typename A, typename... C> string to_string(const A (&v), int x1, int x2, C... coords) { int rnk = rank<A>::value; string tab(t_a_b_s, ' '); string res = ""; bool first = true; if(l_v_l_v_l == 0) res += n_l; res += tab + "["; x1 = min(x1, SIZE(v)), x2 = min(x2, SIZE(v)); auto l = begin(v); advance(l, x1); auto r = l; advance(r, (x2-x1) + (x2 < SIZE(v))); for (auto e = l; e != r; e = next(e)) { if (!first) { res += ", "; } first = false; l_v_l_v_l++; if(e != l){ if(rnk > 1) { res += n_l; t_a_b_s = l_v_l_v_l; }; } else{ t_a_b_s = 0; } res += to_string(*e, coords...); l_v_l_v_l--; } res += "]"; if(l_v_l_v_l == 0) res += n_l; return res; } void dbgm(){;} template<typename Heads, typename... Tails> void dbgm(Heads H, Tails... T){ cout << to_string(H) << " | "; dbgm(T...); }
#define dbgm(...) cout << "[" << #__VA_ARGS__ << "]: "; dbgm(__VA_ARGS__); cout << endl

#define REP(i,a,b) for(int i=(a);i<(b);i++)
#define PER(i,a,b) for(int i=(a);i>(b);i++)
#define SZ(a) int((a).size())
#define ALL(a) (a).begin(), (a).end()
#define MS(s, n) memset(s, n, sizeof(s))
#define IN(t, x) (t.find(x) != t.end())
#define PB push_back
#define MP make_pair
#define VI vector<int>

typedef vector<pair<int, int>> VPII;
typedef pair<int, int> PII;
typedef long long ll;
typedef unsigned long long ull;
const int MOD = (int) 1e9 + 7;

int main() {
    int n;
    cin >> n;
    VI pos;
    VI neg;
    int tmp;
    REP(i,0,n) {
        cin >> tmp;
        if (tmp > 0) pos.PB(tmp);
        else neg.PB(tmp);
    }
    VI ret;
    int x, y;
    if (n == 2) {
        while (SZ(pos)) {
            ret.PB(pos.back());
            pos.pop_back();
        }
        while (SZ(neg)) {
            ret.PB(neg.back());
            neg.pop_back();
        }
        sort(ALL(ret));
        x = ret.back(); ret.pop_back();
        y = ret.back();
        cout << x - y << '\n' << x << ' ' << y << '\n';
        return 0;
    }

    sort(ALL(pos));
    reverse(ALL(pos));
    sort(ALL(neg));

    if (neg.empty()) {
        x = pos.back(); pos.pop_back();
        y = pos.back(); pos.pop_back();
        ret.PB(x);
        ret.PB(y);
        neg.PB(x-y);
    } else if (pos.empty()) {
        x = neg.back(); neg.pop_back();
        y = neg.back(); neg.pop_back();
        ret.PB(x);
        ret.PB(y);
        pos.PB(x-y);
    }

    while (SZ(pos) > 1) {
        x = neg.back(); neg.pop_back();
        y = pos.back(); pos.pop_back();
        ret.PB(x);
        ret.PB(y);
        neg.PB(x-y);
    }
    // pos size 1
    while (!neg.empty()) {
//        dbg(pos);
//        dbg(neg);
        x = pos.back(); pos.pop_back();
        y = neg.back(); neg.pop_back();
        pos.PB(x-y);
        ret.PB(x);
        ret.PB(y);
    }
    cout << pos.back() << '\n';
    for (int i = 0; i < SZ(ret); i+= 2) {
        x = ret[i];
        y = ret[i+1];
        cout << x << ' ' << y << '\n';
    }

    return 0;
}

Measured memory_bytes: 3444