N = int(input())

if N == 1:
    exit(print(1))

# 素数
limit = 10**7
distinct_prime_factor_count = [0]*(limit+1)
primes = []
for i in range(2, limit+1):
    if distinct_prime_factor_count[i] == 0:
        primes.append(i)
        for num in range(i, limit+1, i):
            distinct_prime_factor_count[num] += 1

cnt = [0]*(N + 1)
for prime in primes:
    for num in range(prime, N + 1, prime):
        cnt[num] ^= 1

# 平方
for prime in primes:
    x = prime*prime
    for num in range(x, N + 1, x):
        cnt[num] = -1

ans = 0
for i in range(1, N + 1):
    if cnt[i] != -1:
        ans += (-1)**cnt[i]
print(ans)