from math import sin

k = int(input())

t = [0] * 128
for n in range(1, 128 + 1):
    t[n - 1] = sin(k * n) / (n ** n)

x = 1
while x < 128:
    for i in range(0, 128, x * 2):
        t[i] += t[i + x]
    x *= 2

print(t[0])