CF720F.Array Covering

Misha has an array of integers of length $n$ . He wants to choose $k$ different continuous subarrays, so that each element of the array belongs to at least one of the chosen subarrays.

Misha wants to choose the subarrays in such a way that if he calculated the sum of elements for each subarray, and then add up all these sums, the resulting value was maximum possible.

The first line of input contains two integers: $n$ , $k$ ( $1<=n<=100000$ , $1<=k<=n·(n+1)/2$ ) — the number of elements in the array and the number of different subarrays that must be chosen.

The second line contains $n$ integers $a_{i}$ ( $-50000<=a_{i}<=50000$ ) — the elements of the array.

Output one integer — the maximum possible value Misha can get by choosing $k$ different subarrays.