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>
//package Mem_Round1;

import java.io.*;
import java.util.*;

public class B {
	public static void main(String[] args) throws Exception{ new B(new Reader()); }
	public B(Reader rr) throws IOException{
		int n=rr.ni();
		boolean add2=(n-((int)Math.pow((int)Math.sqrt(n), 2)))>0;
		boolean add4=(n-((int)Math.pow((int)Math.sqrt(n), 2)))>(int)Math.sqrt(n);
		int ans=(int)Math.sqrt(n)*4+((add2)?2:0)+((add4)?2:0);
		System.out.println(ans);
	}
	static class Reader{
		private DataInputStream din;
		private byte[] buffer=new byte[1024];
		private int bufP, bytR;
		public Reader() throws IOException{
			din=new DataInputStream(System.in);
			bufP=bytR=0;
		}
		public Reader(String file) throws IOException{
			din=new DataInputStream(new FileInputStream(file));
			bufP=bytR=0;
		}
		private String rl() throws IOException{
			byte[] buf=new byte[1024];
			int cnt=0, c;
			while((c=read())!=-1){
				if(c=='\n') break;
				buf[cnt++]=(byte)c;
			}
			return new String(buf, 0, cnt);
		}
		private int ni() throws IOException{
			int num=0;
			byte c=read();
			while(c<=' ') c=read();
			boolean neg=(c=='-');
			if(neg) c=read();
			do{
				num=num*10+c-'0';
			} while((c=read())>='0'&&c<='9');
			if(neg) return -num;
			return num;
		}
		private long nl() throws IOException{
			long num=0;
			byte c=read();
			while(c<=' ') c=read();
			boolean neg=(c=='-');
			if(neg) c=read();
			do{
				num=num*10+c-'0';
			} while((c=read())>='0'&&c<='9');
			if(neg) return -num;
			return num;
		}
		private double nd() throws IOException{ return Double.parseDouble(ns()); }
		private char nc() throws IOException{ return (char)next(); }
		private String ns() throws IOException{
			int c=next();
			StringBuilder sb=new StringBuilder();
			while(!(isChar(c))){
				sb.appendCodePoint(c);
				c=read();
			}
			return sb.toString();
		}
		private char[] ns(int n) throws IOException{
			char[] buf=new char[n];
			int c=next(), r=0;
			while(r<n&&!(isChar(c))){
				buf[r++]=(char)c;
				c=next();
			}
			return n==r?buf:Arrays.copyOf(buf, r);
		}
		private char[][] nm(int n, int m) throws IOException{
			char[][] map=new char[n][];
			for(int i=0; i<n; i++) map[i]=ns(m);
			return map;
		}
		private int[] na(int n) throws IOException{
			int[] a=new int[n];
			for(int i=0; i<n; i++) a[i]=ni();
			return a;
		}
		private boolean isChar(int c) throws IOException{ return !(c>=33&&c<=126); }
		private int next() throws IOException{ int c; while((c=read())!=-1&&isChar(c)); return c; }
		private byte read() throws IOException{
			if(bufP==bytR){
				bytR=din.read(buffer, bufP=0, 1024);
				if(bytR==-1) buffer[0]=-1;
			}
			return buffer[bufP++];
		}
		public void close() throws IOException{
			if(din==null) return;
			din.close();
		}
	}
}
