n, k = map(int, input().split())
a = list(map(int, input().split()))

if k <= n:
    print(a[k-1])
    exit()

# Compute cumulative XOR array
cumulative_xor = [0] * (n + 1)
for i in range(1, n + 1):
    cumulative_xor[i] = cumulative_xor[i-1] ^ a[i-1]

period = n + 1
k_mod = k % period
k_prev_mod = (k - 1) % period

xk = cumulative_xor[k_mod] if k_mod != 0 else cumulative_xor[0]
xk_prev = cumulative_xor[k_prev_mod] if k_prev_mod != 0 else cumulative_xor[0]

result = xk ^ xk_prev
print(result)