#include <bits/stdc++.h>
using namespace std;
// type alias
typedef long long LL;
typedef pair<int,int> II;
typedef tuple<int,int,int> III;
typedef vector<int> VI;
typedef vector<string> VS;
typedef unordered_map<int,int> MAPII;
typedef unordered_set<int> SETI;
template<class T> using VV=vector<vector<T>>;
// minmax
template<class T> inline T SMIN(T& a, const T b) { return a=(a>b)?b:a; }
template<class T> inline T SMAX(T& a, const T b) { return a=(a<b)?b:a; }
// repetition
#define FORE(i,a,b) for(int i=(a);i<=(b);++i)
#define REPE(i,n)  for(int i=0;i<=(n);++i)
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  for(int i=0;i<(n);++i)
#define FORR(x,arr) for(auto& x:arr)
#define SZ(a) int((a).size())
// collection
#define ALL(c) (c).begin(),(c).end()
// DP
#define MINUS(dp) memset(dp, -1, sizeof(dp))
#define ZERO(dp) memset(dp, 0, sizeof(dp))
// stdout
#define println(args...) fprintf(stdout, ##args),putchar('\n');
// debug cerr
template<class Iter> void __kumaerrc(Iter begin, Iter end) { for(; begin!=end; ++begin) { cerr<<*begin<<','; } cerr<<endl; }
void __kumaerr(istream_iterator<string> it) { (void)it; cerr<<endl; }
template<typename T, typename... Args> void __kumaerr(istream_iterator<string> it, T a, Args... args) { cerr<<*it<<"="<<a<<", ",__kumaerr(++it, args...); }
template<typename S, typename T> std::ostream& operator<<(std::ostream& _os, const std::pair<S,T>& _p) { return _os<<"{"<<_p.first<<','<<_p.second<<"}"; }
#define __KUMATRACE__ true
#ifdef __KUMATRACE__
#define dump(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); __kumaerr(_it, args); }
#define dumpc(ar) { cerr<<#ar<<": "; FORR(x,(ar)) { cerr << x << ','; } cerr << endl; }
#define dumpC(beg,end) { cerr<<"~"<<#end<<": "; __kumaerrc(beg,end); }
#else
#define dump(args...)
#define dumpc(ar)
#define dumpC(beg,end)
#endif

// $ cp-batch SuccessiveSubtraction | diff SuccessiveSubtraction.out -
// $ g++ -std=c++14 -Wall -O2 -D_GLIBCXX_DEBUG -fsanitize=address SuccessiveSubtraction.cpp && ./a.out

/*
 
 6/15/2019
 
 5:16-5:53 RE
 6:00 AC
 
 https://img.atcoder.jp/diverta2019-2/editorial.pdf
 
 */

const int MAX_N=1e6+1;
LL A[MAX_N];
int N;

void solve() {
  sort(A,A+N);
  VI S(N,0);
  /*
  // complex code during the contest
  map<int,int> cnt;
  REP(i,N){
    int x=0;
    if(A[i]>0) x=1;
    else if(A[i]<0) x=-1;
    S[i]=x;
    cnt[x]++;
  }
  if(cnt[0]==0) {
    if(cnt[1]==N) S[0]=-1;
    else if(cnt[-1]==N) S[N-1]=1;
  } else if(cnt[-1]==0) {
    REP(i,N) if(A[i]==0) {
      S[i]=-1;
      break;
    }
  }*/
  // simpler code described in the video editorial
  S[0]=-1,S[N-1]=1;
  FOR(i,1,N-1) S[i]=A[i]>=0?1:-1;
  
  queue<int> Q[2];
  REP(i,N) Q[S[i]>=0].emplace(A[i]);
  assert(SZ(Q[0])&&SZ(Q[1]));
  int x=Q[0].front(); Q[0].pop();
  vector<II> res;
  while(SZ(Q[1])>1) {
    int y=Q[1].front(); Q[1].pop();
    res.emplace_back(x,y);
    x=x-y;
  }
  int y=x; x=Q[1].front(),Q[1].pop();
  res.emplace_back(x,y);
  x=x-y;
  while(SZ(Q[0])) {
    int y=Q[0].front(); Q[0].pop();
    res.emplace_back(x,y);
    x=x-y;
  }
  println("%d", x);
  assert(SZ(res)==N-1);
  FORR(p,res) println("%d %d", p.first, p.second);
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout<<setprecision(12)<<fixed;
  
  cin>>N;
  REP(i,N) cin>>A[i];
  solve();
  
  return 0;
}


Measured memory_bytes: 4472