Magic Formulas

题意翻译

给你 $\large n$ 个数 $\large p_1 \cdots p_n$。 令 $\large q_i=p_i \oplus(i \mod 1)\oplus(i \mod 2)\oplus\cdots\oplus (i \mod n)$。 令 $\large Q=q_1 \oplus q_2\oplus\cdots\oplus q_n$。 求 $\large Q$

题目描述

People in the Tomskaya region like magic formulas very much. You can see some of them below. Imagine you are given a sequence of positive integer numbers $ p_{1} $ , $ p_{2} $ , ..., $ p_{n} $ . Lets write down some magic formulas: Here, "mod" means the operation of taking the residue after dividing. The expression  means applying the bitwise $ xor $ (excluding "OR") operation to integers $ x $ and $ y $ . The given operation exists in all modern programming languages. For example, in languages C++ and Java it is represented by "^", in Pascal — by "xor". People in the Tomskaya region like magic formulas very much, but they don't like to calculate them! Therefore you are given the sequence $ p $ , calculate the value of $ Q $ .

输入输出格式

输入格式

The first line of the input contains the only integer $ n $ ( $ 1<=n<=10^{6} $ ). The next line contains $ n $ integers: $ p_{1},p_{2},...,p_{n} $ ( $ 0<=p_{i}<=2·10^{9} $ ).

输出格式

The only line of output should contain a single integer — the value of $ Q $ .

输入输出样例

输入样例 #1

3
1 2 3

输出样例 #1

3