gets
steps = gets.strip.chars

current = 0
valleys = 0
in_valley = false

steps.each do |dir|
  current += "U" == dir ? 1 : -1
  if 0 == current
    if in_valley
      valleys += 1
      in_valley = false
    end
  elsif 0 > current
    in_valley = true if in_valley == false
  end
end

puts valleys