import java.util.Scanner;
public class Main{
public static void main(String[] args){
Scanner scan = new Scanner(System.in);
while(scan.hasNext()){
int n = scan.nextInt();
getNum(n);
}
scan.close();
}
private static void getNum(int n){
int[] data = new int[n];
boolean[] flag = new boolean[n];
for(int i = 0 ; i < n ; i++){
data[i] = i + 1;
}
int index = 1;
while(index <= n){
for(int i = 0 ; i < n ; i++){
if(data[i] % index == 0){
flag[i] = !flag[i];
}
}
index++;
}
int count = 0 ;
for(int i = 0 ; i < n ; i++){
if(flag[i]){
count++;
}
}
System.out.println(count);
}
}