def f(n):
    for i in range(2, 16384 + 1):
        x = i ** n
        if x > 1000000000000:
            break
        t.append(1 / x)


x = int(input())

t = []
for i in range(x, 128):
    f(i)

t.extend([0] * (128 * 16384 - len(t)))
t.sort()

x = 1
while x < 128 * 16384:
    for i in range(0, 128 * 16384, x * 2):
        t[i] += t[i + x]
    x *= 2

print(int(t[0] * (10 ** 6)))