from heapq import *
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def SI(): return sys.stdin.readline()[:-1]

def main():
    n, m = MI()
    ww = LI()
    hp = []
    for i in range(n): heappush(hp, (ww[(i - 1)%n] + ww[i], i))
    diff=n-m
    used=[False]*n
    while diff:
        s,i=heappop(hp)
        if used[i] or s!=ww[(i-1)%n]+ww[i]:continue
        used[i]=True
        ww[(i-1)%n]=ww[i]=0
        heappush(hp,(ww[(i-2)%n]+ww[(i-1)%n],(i-1)%n))
        heappush(hp,(ww[i]+ww[(i+1)%n],(i+1)%n))
        diff-=1
    print(sum(ww))

main()