Problem: A set of four prime numbers arranged like (a, a + 2, a + 6, a + 8) is called a quadruplet prime number. Of the four prime numbers that make up a quadruplet prime, the largest number is called the size of the quadruplet prime. For example, the smallest prime quadruplet is a set of (5, 7, 11, 13), which is 13 in size. The next largest prime quadruplet is the set of (11, 13, 17, 19), which is 19 in size.

Create a program that takes the integer n (13 ≤ n ≤ 10,000,000) as input and outputs the maximum size of the quadruplet prime numbers whose size is n or less.



Input

A sequence of multiple datasets is given as input. The end of the input is indicated by a single line of zeros. One integer n is given on one row for each dataset.

The number of datasets does not exceed 2000.

Output

Outputs the maximum prime quadruplet size on one line for each input dataset.

Example

Input

13
14
15
16
17
18
19
20
10000
0


Output

13
13
13
13
13
13
19
19
9439

Solution (in JAVA):

Solution:
import java.util.Scanner;

public class Main{
    public static void main(String[] args){
	Scanner sc = new Scanner(System.in);
	int n = 0;
	boolean[] check = new boolean[10000000];
	makePrime(check);
	
	while(sc.hasNext()){
	    n = sc.nextInt();
	    if(n==0) break;

	    System.out.println(checkPrime(check,n));
	}
    }

    static void makePrime(boolean[] check){
	
	for(int i = 1;i*i<check.length;i++){ // テ」ツ?敕」ツつ古」ツ?古ァツエツ?ヲツ閉ーテ」ツ??」ツ?」テ」ツ?淌」ツつ嘉」ツ?敕」ツ?ョテ・ツ?催ヲツ閉ーテ」ツつ稚rueテ」ツ?ォテ」ツ?凖」ツつ?
	    if(!check[i]) notPrime(check,i+1);
	}
    }

    static int checkPrime(boolean[] check,int n){ // テ・ツ崢崚」ツ?、テ・ツュツ静ァツエツ?ヲツ閉ーテ」ツつ津ィツソツ氾」ツ??
	for(int i = n-1;i>=0;i--){ // falseテ」ツつ津」ツ?ソテ」ツ?、テ」ツ?妥」ツ?淌」ツつ嘉」ツ?敕」ツ?ョテ、ツクツ凝」ツ?ィテ」ツ?凝」ツつづィツヲツ凝」ツ?ヲテ」ツ?｛kテ」ツ??」ツ?」テ」ツ?淌」ツつ嘉」ツ?敕」ツつ古」ツ?古ヲツ慊?・ツ、ツァテ」ツ?ョテヲツ閉ーテ」ツ??」ツ?療ィツソツ氾」ツ?療」ツ?。テ」ツつε」ツ??
	    if(!check[i] && !check[i-2] && !check[i-6] && !check[i-8]){
		return i+1;
	    }
	}
	return 0; // テ、ツサツョ
	
    }

    static void notPrime(boolean[] check,int n){ // テァツエツ?ヲツ閉ーテ」ツ??」ツ?」テ」ツ?淌ヲツ閉ーテ」ツ?ョテ・ツ?催ヲツ閉ーテ」ツつ稚rueテ」ツ?ォ
	for(int i = 2;i*n<check.length;i++){
	    check[(n*i)-1] = true;
	}
    }
}