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

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        HashSet<Integer> current = new HashSet<>();
        HashSet<Integer> next = new HashSet<>();
        current.add(0);
        for (int i = 0; i < n; i++) {
            int x = sc.nextInt();
            for (int y : current) {
                if (next.contains(y)) {
                    next.remove(y);
                } else {
                    next.add(y);
                }
                if (next.contains(x + y)) {
                    next.remove(x + y);
                } else {
                    next.add(x + y);
                }
            }
            HashSet<Integer> tmp = next;
            next = current;
            current = tmp;
            next.clear();
        }
        int ans = 0;
        for (int x : current) {
            ans ^= x;
        }
        System.out.println(ans);
    }
}
    
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 String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}