"""
Aufgabe 28
(c) Jürgen Meier
www.3d-meier.de
14.12.2025
"""

import math


k = 1000    # Endwert Laufvariable
s = 0.0     # Summe

for k in range(1, k+1):
    a = 2.0*k+1
    b = k*k*(k+1)
    s = s + a/b    

print(s)

print("-------------------")
print(1+math.pi**2/6)