N = int(input())
def gcd(a,b):
    if b==0:return a
    return gcd(b,a%b)
P = list(range(N+1))
for i in range(2,N+1):
    if i*i>N:break
    for j in range(i*i,N+1,i):
        P[j] = P[i]
dp = [0]*(N+1)
memo = {}
def dp(x):
    if x==1:return 0
    if P[x]==x:return x/(x-1)
    if x in memo:return memo[x]
    cnt = 0
    for i in range(1,x):
        cnt += dp(gcd(x,i))
    memo[x] = cnt/(x-1)+x/(x-1)
    return memo[x]
print(dp(N))