import java.io.File;
import java.io.FileNotFoundException;
import java.math.BigInteger;
import java.util.Scanner;
import java.util.Set;
import java.util.Map;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;

public class Main {
	
	private static Scanner sc;
	
	private static Set<Integer>[][] C;
	
	private static int getK(int v) {
		// TODO Auto-generated method stub
		int ret = 0;
		while(v > 1) {
			ret++;
			v/=2;
		}
		return ret;
	}
	
	private static Set<Integer> possibles(List<Integer> arr,int start,int end) {
		// TODO Auto-generated method stub
		if(C[start][end]!=null) {
			return C[start][end];
		}

		Set<Integer> ret = new HashSet<Integer>();
		
		for(int i=start;i<=end;i++) {
			ret.add(arr.get(i));
		}
		
		for(int i=start;i<end;i++) {
			Set<Integer> arr1 = possibles(arr,start,i);
			Set<Integer> arr2 = possibles(arr,i+1,end);
			ret.addAll(arr1);
			ret.addAll(arr2);
			for(Integer v : arr1) {
				if(arr2.contains(v)) {
					ret.add(v+1);
				}
			}
		}
		
		C[start][end] = ret;
		return C[start][end];
	}
	
	public static void main(String[] args) throws FileNotFoundException {
		// TODO Auto-generated method stub
		sc = new Scanner(System.in);
		int n = sc.nextInt();
		C = new Set[n][];
		for(int i=0;i<n;i++) {
			C[i] = new Set[n];
		}
		List<Integer> P = new ArrayList<Integer>();
		for(int i=0;i<n;i++) {
			int v = getK(sc.nextInt()); 
			P.add(v);
		}
		
		Set<Integer> arr = possibles(P,0,n-1);
		
		int m = 0;
		for(Integer v : arr) {
			m = Math.max(m, v);
		}
		
		BigInteger ret = new BigInteger("1");
		for(int i=0;i<m;i++) {
			ret = ret.multiply(new BigInteger("2"));
		}
		
		System.out.println(ret);
	}

}