#!/usr/koeki/bin/ruby
#coding: euc-jp


def func (x)
  return Math::sqrt(9 - x * x)
end

def trapezoid(x1, x2)
  n = 100.0
  d = (x2 - x1) / n
  x = x1
  s = 0
  1.upto(n - 1) do |i|
    x += d
    s += func(x)
  end
  int = d * ((func(x1) + func(x2)) / 2 + s)
end

print "x_1: "
a1 = gets.chomp.to_f
print "x_2: "
a2 = gets.chomp.to_f

puts "(#{a1}, #{a2}): #{trapezoid(a1,a2)}"