#input of int(split by space)
def get_i()
  return gets.chomp.split(" ").map(&:to_i)
end
#input of float(split by space)
def get_f()
  return gets.chomp.split(" ").map(&:to_f)
end
#input of string(split by space)
def get()
  return gets.chomp.split(" ")
end
#input of string(split per one character)
def get_nsp()
  return gets.chomp.split("")
end
#yes or no decision
def yn_judge(bool,y="Yes",n="No")
  return bool ? y : n 
end
#create of array
def array(size1,init=nil,size2=-1)
  if size2==-1
      return Array.new(size1){init}
  else
      return Array.new(size2){Array.new(size1){init}}
  end
end

def max(a,b)
    return a>b ? a : b
end

def min(a,b)
    return a>b ? b : a
end

INF=Float::INFINITY

N=gets.to_i
a=get_i.sort!
cnt_ps=a.count{|x| x>=0}
cnt_ng=a.count{|x| x<=0}
if cnt_ps==N
    ans=[]
    num1=a.pop
    num2=a.shift
    a.each do|a_|
        ans.push([num2,a_])
        num2-=a_
    end
    ans.push([num1,num2])
    num1-=num2
    puts num1
    ans.each do|arr|
        puts arr.join(" ")
    end
elsif cnt_ng==N
    ans=[]
    num=a.pop
    a.each do|a_|
        ans.push([num,a_])
        num-=a_
    end
    puts num
    ans.each do|arr|
        puts arr.join(" ")
    end
else
    ps=a.select{|x| x>0}
    ng=a.select{|x| x<=0}
    num1=ps.pop
    num2=ng.pop
    ans=[]
    ps.each do|n|
        ans.push([num2,n])
        num2-=n
    end
    ng.each do|n|
        ans.push([num1,n])
        num1-=n
    end
    ans.push([num1,num2])
    num1-=num2
    puts num1
    ans.each do|arr|
        puts arr.join(" ")
    end
end