package main

import (
	"fmt"
)

func main() {
	var n int64
	if _, err := fmt.Scan(&n); err != nil {
		return
	}

	var sum int64 = n
	for n > 1 {
		var p int64 = 2
		for p*p <= n {
			if n%p == 0 {
				break
			}
			p++
		}
		if p*p > n {
			p = n
		}
		n /= p
		sum += n
	}
	fmt.Println(sum)
}