题目描述
The beauty of a sequence a of length n is defined as $a_1 \oplus \cdots \oplus a_n$, where $\oplus$ denotes the bitwise exclusive or (XOR).
You are given a sequence A of length N. Snuke will insert zero or more partitions in A to divide it into some number of non-empty contiguous subsequences.
There are 2^{N-1} possible ways to insert partitions. How many of them divide A into sequences whose beauties are all equal? Find this count modulo 10^{9}+7.
Constraints
- All values in input are integers.
- $1 \leq N \leq 5 \times 10^5$
- $0 \leq A_i < 2^{20}$
Input
Input is given from Standard Input in the following format:
N
$A_1 A_2 \ldots A_{N}$
Output
Print the answer.
Examples
Input
3
1 2 3
Output
3
Input
3
1 2 2
Output
1
Input
32
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Output
147483634
Input
24
1 2 5 3 3 6 1 1 8 8 0 3 3 4 6 6 4 0 7 2 5 4 6 2
Output
292
输入格式
见题面
输出格式
见题面