import java.util.*;
fun main() {
    val sc=Scanner(System.`in`)
    val n=sc.nextInt();
    var cnt:Long=0L
    for(i in 1..1000000){
        for(j in 1..1000000){
            if(i*j<n){
                cnt++
            }else {
                break
            };
        }
    }
    println(cnt)
}