N = int(input())
A = list(map(int, input().split()))
U = sum(A)

dp = [0] * (U + 1)
dp[0] = 1
for a in A:
    for i in reversed(range(a, U+1)):
        dp[i] += dp[i-a]
        dp[i] %= 2

ans = 0
for i in range(U+1):
    if dp[i]:
        ans ^= i

print(ans)