N = gets.to_i
S = gets.chomp
count = 0

(N - 2).times do |i|
  (1..(N - 3) / 2 + 1).each do |j|
    count += 1 if "#{S[i]}#{S[i + j]}#{S[i + 2 * j]}" == 'UMG'
  end
end

puts count