def lscan; gets.split.map(&:to_f); end

# https://ja.wikipedia.org/wiki/%E3%82%A4%E3%83%B3%E3%83%89%E3%82%BE%E3%82%A6
h,r = lscan
p -8.245 + 6.807 * h + 7.073 * r*Math::PI*2.0