Problem Statement

For a sequence S of positive integers and positive integers k and l, S is said to belong to level (k,l) when one of the following conditions is satisfied:

• The length of S is 1, and its only element is k.
• There exist sequences $T_1,T_2,...,T_m (m \geq l)$ belonging to level (k-1,l) such that the concatenation of T_1,T_2,...,T_m in this order coincides with S.

Note that the second condition has no effect when k=1, that is, a sequence belongs to level (1,l) only if the first condition is satisfied.
Given are a sequence of positive integers A_1,A_2,...,A_N and a positive integer L.
Find the number of subsequences $A_i,A_{i+1},...,A_j (1 \leq i \leq j \leq N)$ that satisfy the following condition:

• There exists a positive integer K such that the sequence A_i,A_{i+1},...,A_j belongs to level (K,L).

Input

Input is given from Standard Input in the following format:
N L
A_1 A_2 ... A_N

Output

Print the number of subsequences $A_i,A_{i+1},...,A_j (1 \leq i \leq j \leq N)$ that satisfy the condition.

Constraints

• $1 \leq N \leq 2 \times 10^5$
• $2 \leq L \leq N$
• $1 \leq A_i \leq 10^9$

Sample Input 1

9 3
2 1 1 1 1 1 1 2 3

Sample Output 1

22

For example, both of the sequences (1,1,1) and (2) belong to level (2,3), so the sequence (2,1,1,1,1,1,1) belong to level (3,3).

Sample Input 2

9 2
2 1 1 1 1 1 1 2 3

Sample Output 2

41

Sample Input 3

15 3
4 3 2 1 1 1 2 3 2 2 1 1 1 2 2

Sample Output 3

31

见题面 Input 部分

见题面 Output 部分