from functools import reduce
from operator import xor


def main():
    N, K = map(int, input().split())
    A = list(map(int, input().split()))

    if K <= N:
        print(A[K-1])
        return

    match (K-N-1) % (N+1):
        case 0:
            print(reduce(xor, A))
        case num:
            print(A[num-1])


if __name__ == "__main__":
    main()