# your code goes here
n = int(input())
a = list(map(int, input().split()))
K = int(input())
p = [0] * n
p[0] = a[0]
for i in range(1, n):
    p[i] = p[i - 1] ^ a[i]
max_l = 0
mp = {0: -1}
for j in range(n):
    RHS = p[j] ^ K
    if RHS in mp:
        i = mp[RHS] + 1
        length = j - i + 1
        max_l = max(max_l, length)
    if p[j] not in mp:
        mp[p[j]] = j
print(max_l)