n = gets.chomp.to_i
a = gets.chomp

if a.include?(' ')
  puts "assert"
  exit
end

a = a.to_i
b = gets.chomp.to_i
c = gets.chomp.to_i

puts [a, b, c].combination(2).map{|c| c[0] + c[1]}.sort.uniq.reverse[1]