#include<bits/stdc++.h>
using namespace std;
unsigned long long n;
bool isPrime[1000000];
int prime[1000000],pi[1000000],phi[60][5],size[5];
int getprime() 
{
    int cnt=0;
    isPrime[0]=isPrime[1]=true;
    pi[0]=pi[1]=0;
    for(int i=2;i<1000000;++i) 
	{
        if(!isPrime[i]) 
			prime[++cnt]=i;
        pi[i]=cnt;
        for(int j=1;j<=cnt && i*prime[j]<1000000;++j) 
		{
            isPrime[i*prime[j]]=true;
            if(i%prime[j]==0) 
				break;
        }
    }
    return cnt;
}
int sqrt2(long long x) 
{
    long long r=(long long)sqrt(x-0.1);
    while(r*r<=x)
		++r;
    return int(r-1);
}
int sqrt3(long long x) 
{
    long long r=(long long)cbrt(x-0.1);
    while(r*r*r<=x) 
		++r;
    return int(r-1);
}
long long getphi(long long x, int s) 
{
    if(s==0) 
		return x;
    if(s<=2) 
		return phi[x%size[s]][s]+(x/size[s])*phi[size[s]][s];
    if(x<=prime[s]*prime[s]) 
		return pi[x]-s+1;
    if(x<=prime[s] * prime[s]*prime[s] && x<1000000) 
	{
        int s2=pi[sqrt2(x)];
        long long ans=pi[x]-(s2+s-2)*(s2-s+1)/2;
        for(int i=s+1;i<=s2;++i) 
			ans+=pi[x/prime[i]];
        return ans;
    }
    return getphi(x,s-1)-getphi(x/prime[s],s-1);
}
long long getpi(long long x) 
{
    if(x<1000000) 
		return pi[x];
    long long ans=getphi(x,pi[sqrt3(x)])+pi[sqrt3(x)]-1;
    for(int i=pi[sqrt3(x)]+1,ed=pi[sqrt2(x)];i <= ed;++i) 
		ans-=getpi(x/prime[i])-i+1;
    return ans;
}
long long Meissel_Lehmer(long long x) 
{
    if(x<1000000) 
		return pi[x];
    int a=(int)Meissel_Lehmer(sqrt2(sqrt2(x)));
    int b=(int)Meissel_Lehmer(sqrt2(x));
    int c=(int)Meissel_Lehmer(sqrt3(x));
    long long sum=getphi(x,a)+(long long)(b+a-2)*(b-a+1)/2;
    for(int i=a+1;i<=b;i++) 
	{
        long long w=x/prime[i];
        sum-=Meissel_Lehmer(w);
        if(i>c) 
			continue;
        long long lim=Meissel_Lehmer(sqrt2(w));
        for(int j=i;j <= lim;j++) 
			sum-=Meissel_Lehmer(w/prime[j])-(j-1);
    }
    return sum;
}
int main() 
{
    getprime();
    size[0]=1;
    for(int i=0;i <= 50;++i) 
		phi[i][0]=i;
    for(int i=1;i <= 2;++i) 
	{
        size[i]=prime[i]*size[i-1];
        for(int j=1;j<=50;++j) 
			phi[j][i]=phi[j][i - 1]-phi[j/prime[i]][i-1];
    }
    cin>>n;
    cout<<Meissel_Lehmer(n);
    return 0;
}