import java.util.*;

public class Main {
    
    public static void main(String[] args) {
        
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        long K = sc.nextInt();
        long[] A = new long[N+1];
        for( int i = 0; i < N; i++ ) {
            A[i] = sc.nextLong();
            A[N] ^= A[i];
        }
        
        int k = (int)((K-1)%(N+1));
        System.out.println(A[k]);
        
    }
    
}