# frozen_string_literal: true

def solve(t_and_s, result)
  if t_and_s.empty?
    result
  else
    solve(t_and_s[1..-1], (case t_and_s.first[0]
                           when '0'
                             "#{result}#{t_and_s.first[1]}"
                           when '1'
                             "#{t_and_s.first[1]}#{result}"
                           end))
  end
end

N = gets.to_i
T = N.times.map { gets.chomp.split }

RESULT = solve(T, '')

puts RESULT