ef to_t9(s)
  l = {
      'a' => '2',
      'b' => '22',
      'c' => '222',
      'd' => '3',
      'e' => '33',
      'f' => '333',
      'g' => '4',
      'h' => '44',
      'i' => '444',
      'j' => '5',
      'k' => '55',
      'l' => '555',
      'm' => '6',
      'n' => '66',
      'o' => '666',
      'p' => '7',
      'q' => '77',
      'r' => '777',
      's' => '7777',
      't' => '8',
      'u' => '88',
      'v' => '888',
      'w' => '9',
      'x' => '99',
      'y' => '999',
      'z' => '9999',
      'A' => '# 2',
      'B' => '# 22',
      'C' => '# 222',
      'D' => '# 3',
      'E' => '# 33',
      'F' => '# 333',
      'G' => '# 4',
      'H' => '# 44',
      'I' => '# 444',
      'J' => '# 5',
      'K' => '# 55',
      'L' => '# 555',
      'M' => '# 6',
      'N' => '# 66',
      'O' => '# 666',
      'P' => '# 7',
      'Q' => '# 77',
      'R' => '# 777',
      'S' => '# 7777',
      'T' => '# 8',
      'U' => '# 88',
      'V' => '# 888',
      'W' => '# 9',
      'X' => '# 99',
      'Y' => '# 999',
      'Z' => '# 9999',
      '1' => '11111',
      '2' => '2222',
      '3' => '3333',
      '4' => '4444',
      '5' => '5555',
      '6' => '6666',
      '7' => '77777',
      '8' => '8888',
      '9' => '99999',
      '0' => '00',
      '.' => '1',
      ',' => '11',
      '?' => '111',
      '!' => '1111',
      "'" => '*',
      '-' => '**',
      '+' => '***',
      '=' => '****',
      ' ' => '0'
  }
  a = s.chars
  r = []

  # create result array of chars
  a.each_with_index do |e, i|
    if s[i] == s[i+1]
      r << l[e]
      r << '_'
    else
      r << l[e]
    end
    r << ' '
  end

  # but we do not want to type # before each symbol
  # lets just count how many #'s we have'
  r = r.join.split(' ')
  h = 0
  q = []
  r.each_with_index do |e2, i2|
    if e2 == '#'
      h += 1
      q << i2
    end
  end


  # if we have more than 1 '#' in result we should make some cleaning
  # lets create array of indexes where we want add additional '#' and remove others '#'
  ad = []
  if h > 1
    q.each_with_index do |e3, i3|
      if q[i3 - 1].to_i - q[i3 - 2].to_i == 2 && q[i3].to_i - q[i3 - 1].to_i > 2
        ad << { a: q[i3 - 1] + 2 }
      end
      if q[i3].to_i - q[i3 - 1].to_i == 2 && q[i3 + 1] == nil
        ad << { a: q[i3] + 2 }
      end
      if q[i3 + 1].to_i - q[i3].to_i == 2
        r[e3] = '##'
        ad << { d: q[i3 + 1] }
      end
    end
  end

  # if this array size more than 0 let's go reverse on it (so we won't remove any usable symbols)
  if ad.size > 0
    ad.reverse_each do |e4|
      if e4[:d] != nil
        r.delete_at(e4[:d])
      elsif e4[:a] != nil
        r.insert(e4[:a], '#')
      end
    end
  end


  # returning result
  r.join(' ')
end