Get Minimum Moves to Zero

The array has even length. One operation chooses any 0≤L≤R<n, computes the XOR x of all elements in the range before the operation, then sets every element in the range to x simultaneously. Find the minimum number of operations to make every element zero.

输入格式

The first line contains an even n; the second line contains the array. The original text only specifies that n is even; this site uses 2≤n≤200000; 0≤element<2^20.

输出格式

Output a single integer, the answer.

样例 1

输入：

2
0 0

输出：

0

样例 2

输入：

2
3 3

输出：

1

样例 3

输入：

2
1 2

输出：

2

样例说明

The answers are 0, 1 and 2. Third example: 1,2→3,3→0,0.