from collections import defaultdict

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        group_members = defaultdict(list)
        for member in range(self.n):
            group_members[self.find(member)].append(member)
        return group_members

    def __str__(self):
        return '\n'.join(f'{r}: {m}' for r, m in self.all_group_members().items())

import heapq
N,K = list(map(int,input().split()))
A = list(map(int,input().split()))

def check(n):
    SUM = sum(max(i-n,0) for i in A)
    return SUM <= K

ng,ok = -1,10**10
while(ok - ng > 1):
    mid = (ok+ng)//2
    if(check(mid)):
        ok = mid
    else:
        ng = mid

K -= sum(max(i-ok,0) for i in A)
A = [min(i,ok) for i in A]

uf = UnionFind(N)
for i in range(N-1):
    if(A[i] == A[i+1]):
        uf.union(i,i+1)

q = [(-A[i], uf.size(i), i) for i in range(N) if i == 0 or not uf.same(i-1,i)]
heapq.heapify(q)
while(K):
    v,size,idx = heapq.heappop(q);v *= -1

    if(A[idx] != v):continue
    if(size != uf.size(idx)):continue
    if(size > K):break

    left,right = -1,-1
    now = idx
    while(now >= 0 and uf.same(idx,now)):
        A[now] -= 1
        K -= 1
        left = now
        now -= 1

    now = idx+1
    while(now < N and uf.same(idx,now)):
        A[now] -= 1
        K -= 1
        right = now
        now += 1

    if(left > 0 and A[left] == A[left-1]):uf.union(left-1,left)
    if(right < N-1 and A[right] == A[right+1]):uf.union(right,right+1)
    if(A[idx] > 0):heapq.heappush(q, (-A[idx], uf.size(idx), idx))

ans = A[0] + A[-1]
for i in range(N-1):
    ans += abs(A[i] - A[i+1])
print(ans)