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public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StreamTokenizer in = new StreamTokenizer(br);
        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));

        in.nextToken();
        int n = (int)in.nval;

        long res = n;

        while (true) {
            int a = find(n);
            n/=a;
            if(n==1){
                res+=1;
                break;
            }else{
                res+=n;
            }
        }

        out.println(res);
        out.flush();
        out.close();
        br.close();
    }

    private static int find(int a) {

        if(a%2==0){
            return 2;
        }

        for(int i=3;i*i<=a;i++){
            if(a%i==0){
                return i;
            }
        }
        return a;
    }