n = gets.to_i
n.times do
  a = gets.chomp.split(//).map(&:to_i)
  while a.size != 1
    b = []
    (0...a.size-1).each do |i|
      x = a[i] + a[i+1]
      while x >= 10
        x = x.to_s.split(//).map(&:to_i).sum
      end
      b << x
    end
    a = b
  end
  p a[0]
end