s=gets.chomp.chars
l=[[0,0]]
s.each do |c|
  if l[-1][1].even?
    if c=="a"
      l << [l[-1][0]-1,l[-1][1]+1]
    elsif c=="b"
      l << [l[-1][0],l[-1][1]+1]
    else
      l << [l[-1][0],l[-1][1]-1]
    end
  else
    if c=="a"
      l << [l[-1][0]+1,l[-1][1]-1]
    elsif c=="b"
      l << [l[-1][0],l[-1][1]-1]
    else
      l << [l[-1][0],l[-1][1]+1]
    end
  end
end
puts l.uniq.size