###############################################################
#https://atcoder.jp/contests/abc249/submissions/71937223
import math

def smallest_prime_facror(n):
    res=list(range(n+1))
    for i in range(2,int(math.isqrt(n))+1):
        if res[i]==i:
            for j in range(i*i,n+1,i):
                if res[j]==j:
                    res[j]=i
    return res

spf=smallest_prime_facror(10000000)

def prime_factorization(n):
    factors={}
    current=n
    while current>1:
        factors[spf[current]]=factors.get(spf[current],0)+1
        current//=spf[current]
    return factors

def divisors(n):
    factors=prime_factorization(n)
    divs=[1]
    for p,e in factors.items():
        m=len(divs)
        mul=1
        for _ in range(e):
            mul*=p
            for i in range(m):
                divs.append(divs[i]*mul)
    return divs

###############################################################

N=int(input())
ans=1
meb=[1,1]
for k in range(2,N+1):
    p=spf[k]
    if k%(p*p)==0:
        meb.append(0)
    else:
        m=-meb[k//p]
        meb.append(m)
        ans+=m
print(ans)