import java.util.*;

public class Main {
    
    public static void main(String[] args) throws Exception {
        
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int ans = 0;
        for( int i = 2; i*i <= N; i++ ) {
            while( N%i == 0 ) {
                ans += i;
                N /= i;
            }
        }
        
        if( N != 1 ) ans += N;
        System.out.println(ans);
        
    }
    
}