package main

import . "fmt"

func main() {
	var n int
	Scan(&n)
	var f [1e5+1]bool
	sum:=0
	for p:=2;p*p<=n;p++ {
		if f[p] {
			continue
		}
		for k:=p;k*k<=n;k+=p {
			f[k]=true
		}
		for t:=p;t*p<=n;t*=p {
			sum+=t*p
		}
	}
	Println(sum)
}