#include<bits/stdc++.h>
using namespace std; 
using ll=long long;
int main() 
{ 
    cin.tie(0)->sync_with_stdio(0); 
    ll n;cin>>n;
    vector<ll>lp(n+1,-1),primes,ans(n+1);
    for(ll i=2;i<=n;i++)
    {
        if(lp[i]!=-1)continue;
        for(ll j=i;j<=n;j+=i)lp[j]=i;
    }
    ans[1]=1;
    for(int i=2;i<=n;i++)
    {
        if(i%(lp[i]*lp[i])==0)ans[i]=0;
        else ans[i]=-ans[i/lp[i]];
    }
    ll sum=0;
    for(int i=1;i<=n;i++)sum+=ans[i];
    cout<<sum<<endl;
}