Problem: The currency system in the Kingdom of Yoax-Musty is strange and fairly inefficient. Like other countries, the kingdom has its own currencty unit denoted by K $ (kingdom dollar). However, the Ministry of Finance issues bills for every value between 1 K $ and (231 - 1) K $ worth.

On the other hand, this system often enables people to make many different values just with a small number of bills. For example, if you have four bills of 1 K $, 2 K $, 4 K $, and 8 K $ worth respectively, you can make any values from 1 K #36; to 15 K $.

In this problem, you are requested to write a program that finds the minimum value that cannot be made with a given set (multiset in a mathematical sense) of bills. For the case with the four bills (1 K $, 2 K $, 4 K $, and 8 K $), since you can make any values up to 15 K $, your program should report 16 K $.



Input

The input consists of two lines. The first line contains an integer N (1 ≤ N ≤ 10000), the number of bills. The second line contains N integers, each of which represents the value of a bill in K $. There may be multiple bills of the same value.

Output

Print the minimum value unable to be made on a line. The value should be given in K $ and without any currency sign or name.

Example

Input




Output

Solution (in JAVA):

Solution:
import java.util.*;
import java.lang.*;
import java.math.*;
import java.io.*;
import static java.util.Collections.*;
import static java.util.Arrays.*;
import static java.lang.Math.*;

// Strange Currency System
// 2012/12/15
public class Main{
	Scanner sc=new Scanner(System.in);

	int n;
	int[] a;

	void run(){
		n=sc.nextInt();
		a=new int[n];
		for(int i=0; i<n; i++){
			a[i]=sc.nextInt();
		}
		solve();
	}

	void solve(){
		sort(a);
		long sum=0;
		for(int i=0; i<=n; i++){
			if(i==n||a[i]>sum+1){
				println(sum+1+"");
				break;
			}
			sum+=a[i];
		}
	}

	void println(String s){
		System.out.println(s);
	}

	public static void main(String[] args){
		new Main().run();
	}
}