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


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

def simpson(x1,x2)
  n = 100.0
  d = (x2 - x1) / n
  x = x1
  s = 0
  odd = 0
  even = 0
  1.upto((n - 1) * 2) do |i|
    x += d
    if i % 2 == 0
      odd += func(x)
    else
      even += func(x)
    end
  end  
  int  = d * (func(x1) + func(x2) + 4 * (odd + func(x2 - d)) + 2 * even) / 3
end

print "x=a_1: "
a1 = gets.chomp.to_i
print "x=a_2: "
a2 = gets.chomp.to_i

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