n = gets.to_i
s = gets.chomp
if s.include? ' '
  puts '"assert"'
  exit
end

a = [s.to_i]
2.times do
  a << gets.to_i
end

puts [a[0] + a[1], a[0] + a[2], a[1] + a[2]].uniq.sort.reverse[1]