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

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        if (n >= 16) {
            System.out.println((1 << 16) - 1);
            return;
        }
        int[] values = new int[n];
        for (int i = 0; i < n; i++) {
            values[i] = sc.nextInt();
        }
        boolean[][] dp = new boolean[n + 1][1 << 16];
        dp[0][0] = true;
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < (1 << 16); j++) {
                int x = values[i - 1];
                for (int k = 0; k < 16 && !dp[i][j]; k++) {
                    dp[i][j] = dp[i - 1][j ^ (j & x)];
                    x = shift(x);
                }
            }
        }
        int ans = 0;
        for (int i = 0; i < (1 << 16); i++) {
            if (dp[n][i]) {
                ans = i;
            }
        }
        System.out.println(ans);
    }
    
    static int shift(int x) {
        return x % 2 * (1 << 15) + x / 2;
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}