import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		sc.close();

		if (n == 1) {
			System.out.println(0);
		} else {
			Map<Integer, Integer> soinsu = bunkai(n);
			int ans = 0;
			for (int k : soinsu.keySet()) {
				ans += k * soinsu.get(k);
			}
			System.out.println(ans);
		}
	}

	static Map<Integer, Integer> bunkai(int n) {
		Map<Integer, Integer> soinsu = new HashMap<>();
		int end = (int) Math.sqrt(n);
		int d = 2;
		while (n > 1) {
			if (n % d == 0) {
				n /= d;
				soinsu.put(d, soinsu.getOrDefault(d, 0) + 1);
				end = (int) Math.sqrt(n);
			} else {
				if (d > end) {
					d = n - 1;
				}
				d++;
			}
		}
		return soinsu;
	}
}