题目描述
Problem Statement
Snuke has $a permutation (P_0,P_1,\cdots,P_{N-1})$ of $(0,1,\cdots,N-1)$.
Now, he will perform the following operation exactly once:
- Choose K consecutive elements in P and sort them in ascending order.
Find the number of permutations that can be produced as P after the operation.
Input
Input is given from Standard Input in the following format:
N K
$P_0 P_1 \cdots P_{N-1}$
Output
Print the number of permutations that can be produced as P after the operation.
Constraints
- $2 \leq N \leq 200000$
- $2 \leq K \leq N$
- $0 \leq P_i \leq N-1$
- $P_0,P_1,\cdots,P_{N-1}$ are all different.
- All values in input are integers.
Sample Input 1
5 3
0 2 1 4 3
Sample Output 1
2
Two permutations can be produced as P after the operation: (0,1,2,4,3) and (0,2,1,3,4).
Sample Input 2
4 4
0 1 2 3
Sample Output 2
1
Sample Input 3
10 4
2 0 1 3 7 5 4 6 8 9
Sample Output 3
6
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
5 3
0 2 1 4 3
样例输出
2