import math
if __name__ == "__main__":
    # 4.1
    series_value = round(math.pi**2/6, 6)
    approximate_value = 0
    divider = 1
    while series_value != round(approximate_value, 6):
        approximate_value += 1/divider**2
        divider += 1
    print("The sum equals", series_value, "after adding", divider-1, "reciprocal square numbers.")