import sys
from collections import deque, Counter
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353

n = ii()
a = li()

dp = 1

for v in a:
    dp = dp ^ (2 ** v * dp)
ans = 0
cnt = 0
while dp > 0:
    if dp % 2:
        ans ^= cnt
    dp //= 2
    cnt += 1
print(ans)