#include <bits/stdc++.h>
using namespace std;
int main(void){
    const int spfs=10000001;
    long long spf[spfs]={};
    vector<int>mobius(spfs,1);
    for(long long i=2;i<spfs;i++){
        if(spf[i]==0){
            spf[i]=i;
            for(long long j=i;j<spfs;j+=i){
                if(spf[j]==0)spf[j]=i;
                mobius[j]*=(j%(i*i)==0?0:-1);
            }
        }
    }
    int ans=0;
    int n;
    cin>>n;
    for(int i=0;i<n;i++)ans+=mobius[i+1];
    cout<<ans<<endl;
    return 0;
}