g, c, p = gets.strip.split.map{|e| e.to_i}
hands = {G:g, C:c, P:p}
s = gets.strip
score = 0
s.each_char { |chr|
  case chr
  when 'P'
    if hands[:C] > 0
      score += 3
      hands[:C] -= 1
    elsif hands[:P] > 0
      score += 1
      hands[:P] -= 1
    elsif hands[:G] > 0
      hands[:G] -= 1
    end

  when 'C'
    if hands[:G] > 0
      score += 3
      hands[:G] -= 1
    elsif hands[:C] > 0
      score += 1
      hands[:C] -= 1
    elsif hands[:G] > 0
      hands[:P] -= 1
    end

  when 'G'
    if hands[:P] > 0
      score += 3
      hands[:P] -= 1
    elsif hands[:G] > 0
      score += 1
      hands[:G] -= 1
    elsif hands[:C] > 0
      hands[:C] -= 1
    end
  end
}

puts score