P, Q, R = gets.split.map(&:to_i)

box1 = Rational(P, P + Q + R)
box2 = Rational(Q, P + Q + R)
box3 = Rational(R, P + Q + R)

puts [box1, box2, box3, 1.0 - box1, 1.0 - box2, 1.0 - box3].max.to_f