c,d = gets.split.map(&:to_i)
c = Rational(c)
d = Rational(d)

a = Rational(20,13)*c - Rational(8,13)*d
b = -Rational(7,13)*c + Rational(21,13)*d

x1 = (a<0 || b<0) ? 0 : a+2*b

p ([[Rational(4,3)*c,Rational(4,1)*d].min,[Rational(7,2)*c,Rational(7,5)*d].min*2,x1].max*1000).to_f