Edward just lost his Anki streak of 981 days! Completely panic-stricken, he scrambles for ways to recover his lost streak. Luckily, he remembered that the streak calculator works based on Anki's time zone, and that changing the time zone could have the potential to recover some of his streak. Specifically, Edward has logged
reviews, the
-th review at minute
. In his world, each day consists of
minutes. If he picks a time zone that resets at minute
, then each day spans the minutes
for some integer
. A day is considered active if Edward did at least one review that day, and a streak is a consecutive sequence of active days. Your job is to determine the longest possible length of the longest streak, given that Edward picks an optimal value of
.
Constraints


Subtask 1 [5%]

Subtask 2 [20%]

Subtask 3 [75%]
No additional constraints.
Input Specification
The first line contains
integers
and
.
The next line contains
space-separated integers
. These are given in non-decreasing order.
Output Specification
Output the length of the longest streak, given that Edward picks an optimal value of
.
Sample Input
Copy
5 3
3 5 5 7 16
Sample Output
Copy
3
Explanation for Sample
Edward can pick a reset time of
. Then, the
th day consists of minutes
, the
st day consists of minutes
, the
nd day consists of minutes
, and so on. Days
, and
are active, so the longest streak is
days.
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