#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define each(x, y) for (auto &x : y)
#define all(a) (a).begin(), (a).end()
#define bit(b) (1ll << (b))
#define uniq(v) (v).erase(unique(all(v)), (v).end())

using namespace std;

using i32 = int;
using i64 = long long;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << '\n'; exit(0); }
inline void no() { cout << "No" << '\n'; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { return a / gcd(a, b) * b; }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> inline void amax(T &x, T y) { if (x < y) x = y; }
template <typename T> inline void amin(T &x, T y) { if (x > y) x = y; }
template <typename T> inline T power(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { for (auto &x : v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, const vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }

void solve() {
  int n; cin >> n;
  vi32 a(n); cin >> a;
  pqasc<int> pl;
  pqdesc<int> mi;
  rep(i, n) {
    if (a[i] >= 0) pl.push(a[i]);
    else mi.push(a[i]);
  }
  vector<pair<int, int>> ans;
  rep(i, n - 1) {
    if (i == n - 2) {
      if (pl.size() == 0) {
        auto x = mi.top(); mi.pop();
        auto y = mi.top(); mi.pop();
        ans.push_back({x, y});
        pl.push(x - y);
      } else if (mi.size() == 0) {
        auto x = pl.top(); pl.pop();
        auto y = pl.top(); pl.pop();
        ans.push_back({y, x});
        pl.push(y - x);
      } else {
        auto x = pl.top(); pl.pop();
        auto y = mi.top(); mi.pop();
        ans.push_back({x, y});
        pl.push(x - y);
      }
      continue;
    }
    if (pl.size() == 0) {
      auto x = mi.top(); mi.pop();
      auto y = mi.top(); mi.pop();
      ans.push_back({x, y});
      pl.push(x - y);
    } else if (mi.size() == 0) {
      auto x = pl.top(); pl.pop();
      auto y = pl.top(); pl.pop();
      ans.push_back({x, y});
      mi.push(x - y);
    } else {
      auto x = pl.top(); pl.pop();
      auto y = mi.top(); mi.pop();
      if (pl.size() == 0) {
        ans.push_back({x, y});
        pl.push(x - y);
      } else if (mi.size() == 0) {
        ans.push_back({y, x});
        mi.push(y - x);
      } else {
        ans.push_back({x, y});
        pl.push(x - y);
      }
    }
  }
  cout << pl.top() << '\n';
  rep(i, n - 1) {
    cout << ans[i].first << " " << ans[i].second << '\n';
  }
}


Measured memory_bytes: 3700