#!/usr/bin/env python
#Author: Shriphani Palakodety

import math

def solve(x):
	return 2*((5+(x)**3)**(1.0/4.0)) 

nums=[0, 1.0/4.0, 2.0/4.0, 3.0/4.0, 1.0, 5.0/4.0, 6.0/4.0, 7.0/4.0, 2.0 ]
solu = []
for i in xrange(len(nums)):
	if i == 0 or i == len(nums)-1:
		solu.append(solve(nums[i]))
	elif i%2!=0:
		solu.append(4*solve(nums[i]))
	else:
		solu.append(2*solve(nums[i]))
print sum(solu) * 1.0/12.0