Your security guard friend recently got a new job at a new security company. The company requires him to patrol an area of the city encompassing exactly N city blocks, but they let him choose which blocks. That is, your friend must walk the perimeter of a region whose area is exactly N blocks. Your friend is quite lazy and would like your help to find the shortest possible route that meets the requirements. The city is laid out in a square grid pattern, and is large enough that for the sake of the problem it can be considered infinite.

Input

Input will consist of a single integer N (1 ≤ N ≤ 106), the number of city blocks that must be enclosed by the route.

Output

Print the minimum perimeter that can be achieved.

Examples

Input

4


Output

8


Input

11


Output

14


Input

22


Output

20

Note

Here are some possible shapes for the examples:

<image>
import java.util.*;
import java.math.*;
import java.io.*;
import java.text.*;

public class A {

    //public static PrintWriter pw;
    public static PrintWriter pw = new PrintWriter(System.out);

    public static void solve() throws IOException {
    //	pw=new PrintWriter(new FileWriter("C:\\Users\\shree\\Downloads\\small_output_in"));
        FastReader sc = new FastReader();
        int n=sc.I();
        int ans=Integer.MAX_VALUE;
        for(int l1=1;l1<=n;l1++){

            int per=2*l1+(n/l1)*2;
            if(n%l1!=0) per+=2;
            ans=Math.min(ans,per);
        }
        pw.println(ans);
        pw.close();

    }

    public static void main(String[] args) {
        new Thread(null, new Runnable() {
            public void run() {
                try {

                    solve();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }, "1", 1 << 26).start();

    }

    static BufferedReader br;
    static long M = (long) 1e9 + 7;

    static class FastReader {

        StringTokenizer st;

        public FastReader() throws FileNotFoundException {
            //br=new BufferedReader(new FileReader("C:\\Users\\shree\\Downloads\\B-small-practice.in"));
            br = new BufferedReader(new InputStreamReader(System.in));

        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int I() {
            return Integer.parseInt(next());
        }

        long L() {
            return Long.parseLong(next());
        }

        double D() {
            return Double.parseDouble(next());
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }

        public boolean hasNext() throws IOException {
            while (st == null || !st.hasMoreTokens()) {
                String s = br.readLine();
                if (s == null) {
                    return false;
                }
                st = new StringTokenizer(s);
            }
            return true;
        }

    }
}