CF665E Beautiful Subarrays

One day, ZS the Coder wrote down an array of integers $ a $ with elements $ a_{1},a_{2},...,a_{n} $ . A subarray of the array $ a $ is a sequence $ a_{l},a_{l+1},...,a_{r} $ for some integers $ (l,r) $ such that $ 1

The first line contains two integers $ n $ and $ k $ ( $ 1

Print the only integer $ c $ — the number of beautiful subarrays of the array $ a $ .