
Score : 700 points
Problem StatementSnuke 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.
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.
InputInput is given from Standard Input in the following format:
N K
P_0 P_1 \cdots P_{N-1}
OutputPrint the number of permutations that can be produced as P after the operation.
Sample Input 15 3
0 2 1 4 3
Sample Output 12
Two permutations can be produced as P after the operation: (0,1,2,4,3) and (0,2,1,3,4).
Sample Input 24 4
0 1 2 3
Sample Output 21
Sample Input 310 4
2 0 1 3 7 5 4 6 8 9
Sample Output 36
