#! ruby
# yukicoder My Practice
# author: Leonardone @ NEETSDKASU

def gs() gets.chomp end
def gi() gets.to_i end
def gss() gets.chomp.split end
def gis() gss.map(&:to_i) end
def nmapf(n,f) n.times.map{ __send__ f } end
def arr2d(h,w,v=0) h.times.map{[v] * w} end
def ngs(n) nmapf n,:gs end
def ngi(n) nmapf n,:gi end
def ngss(n) nmapf n,:gss end
def ngis(n) nmapf n,:gis end
def for2p(hr,wr,&pr) hr.each{|i|wr.each{|j|pr.call(i,j)}} end

N, M = gis
W = gis

if M < 2
    puts 0
    exit
end

z = [true] * N

ans = W.inject(:+)

if N == M
    puts ans
    exit
end

if N - M == 1
    puts (ans - W.rotate(-1).zip(W).map{|x,y|x+y}.min)
    exit
end

sel = N

bans = nil

20.times {
    
    while sel > M
        j = nil
        cst = nil
        N.times do |i|
            next if !z[i]
            tmp = 0
            tmp += W[i - 1] if z[i - 1]
            tmp += W[i] if z[(i + 1) % N]
            if j.nil? || tmp < cst
                j = i
                cst = tmp
            end
        end
        z[j] = false
        ans -= cst
        sel -= 1
    end
    
    if bans.nil? || ans > bans
        bans = ans
    end
    
    while sel < M + 2
        j = nil
        cst = nil
        N.times do |i|
            next if z[i]
            tmp = 0
            tmp += W[i - 1] if z[i - 1]
            tmp += W[i] if z[(i + 1) % N]
            if j.nil? || tmp > cst
                j = i
                cst = tmp
            end
        end
        z[j] = true
        ans += cst
        sel += 1
    end

}

puts bans