import sys
INF = 1 << 60
MOD = 10**9 + 7 # 998244353
sys.setrecursionlimit(2147483647)
input = lambda:sys.stdin.readline().rstrip()
def resolve():
    n = int(input())
    ans = 0
    for i in range(1, 10001):
        ans += 1 / pow(i, n)
    print(ans)
resolve()