#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned int uint;
typedef unsigned char uchar;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

#define REP(i,x) for(int i=0;i<(int)(x);i++)
#define REPS(i,x) for(int i=1;i<=(int)(x);i++)
#define RREP(i,x) for(int i=((int)(x)-1);i>=0;i--)
#define RREPS(i,x) for(int i=((int)(x));i>0;i--)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();i++)
#define RFOR(i,c) for(__typeof((c).rbegin())i=(c).rbegin();i!=(c).rend();i++)
#define ALL(container) (container).begin(), (container).end()
#define RALL(container) (container).rbegin(), (container).rend()
#define SZ(container) ((int)container.size())
#define mp(a,b) make_pair(a, b)
#define pb push_back
#define eb emplace_back
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );
#define __builtin_popcount __builtin_popcountll
#define endl '\n'

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
    os<<"["; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"]"; return os;
}
template<class T> ostream& operator<<(ostream &os, const set<T> &t) {
    os<<"{"; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"}"; return os;
}
template<class S, class T> ostream& operator<<(ostream &os, const map<S, T> &t) {
    os<<"{"; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"}"; return os;
}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}
template<class S, class T> pair<S,T> operator+(const pair<S,T> &s, const pair<S,T> &t){ return pair<S,T>(s.first+t.first, s.second+t.second);}
template<class S, class T> pair<S,T> operator-(const pair<S,T> &s, const pair<S,T> &t){ return pair<S,T>(s.first-t.first, s.second-t.second);}

const int INF = 1<<28;
const double EPS = 1e-8;
const int MOD = 1000000007;


int T, n, m;

ll solve(vector<int> &pls, vector<int> &mns, int sign) {
    if (pls.empty()) {
        return mns[0];
    }
    if (mns.empty()) {
        return pls[0];
    }
    ll x, y;
    if (pls.size() < mns.size()) {
        y = mns.back(); mns.pop_back();
        x = solve(pls, mns, sign * sign);
    } else {
        x = pls.back(); pls.pop_back();
        y = solve(pls, mns, -sign * sign);
    }
    if (sign == -1) {
        swap(x, y);
    }
    cout << x << " " << y << endl;
    return x - y;
}

int main(int argc, char *argv[]){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    while(cin >> n){
        vi pls, mns;
        REP(i, n) {
            int x;
            cin >> x;
            if (x < 0) mns.push_back(x);
            else pls.push_back(x);
        }
        sort(RALL(pls));
        sort(ALL(mns));
        if (pls.empty()) {
            pls.push_back(mns.back()); mns.pop_back();
        }
        if (mns.empty()) {
            mns.push_back(pls.back()); pls.pop_back();
        }
        cout << accumulate(ALL(pls), 0ll) - accumulate(ALL(mns), 0ll) << endl;
        solve(pls, mns, 1);
    }
    return 0;
}


Measured memory_bytes: 7160