#D7651. XOR Partitioning
XOR Partitioning
XOR Partitioning
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
inputFormat
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}
outputFormat
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
样例
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
147483634