# import系 ---

# 入力用 ---
INT = lambda: int(input())
MI = lambda: map(int, input().split())
MI_DEC = lambda: map(lambda x: int(x) - 1, input().split())
LI = lambda: list(map(int, input().split()))
LI_DEC = lambda: list(map(lambda x: int(x) - 1, input().split()))
LS = lambda: list(input())
LSS = lambda: input().split()



# コード ---
from math import isqrt
N = INT()

# aとbの最大公約数gcdと、a*x - b*y = 1 の特殊解x, y を返す
def extended_gcd(a, b):
    if a == 0:
        return b, 0, 1
    else:
        gcd, x, y = extended_gcd(b % a, a)
        return gcd, y - (b // a) * x, x

# 連立合同式を解く
def culc(A, B, a, b):
    _, x, _ = extended_gcd(A, B)
    return ((A * x) * (b - a) + a) % (A * B)

ans = 0
for i in range(2, (N + 1) // 2):
    clc = culc(i, i-1, 0, N-(i-1))
    x = (N - clc) // (i * (i - 1))
    ans += x - 1 if N % i == 0 else x


print(ans)