I=lambda:map(int,raw_input().split());n,m=I();w=I()
def f(s):
	D={(s,s):0}
	for i in range(n-1):
		T={}
		for(t,h)in D:
			for a in[0,1]:
				if i-n+1<t+a-m<=0:
					k=(t+a,a);u=D[(t,h)]+w[i]*h*a
					if k not in T or T[k]<u:T[k]=u
		D=T
	return max(v+h*s*w[n-1]for(k,h),v in D.items())
print max(f(0),f(1))if(n>m)*(m>0)else[0,sum(w)][m>0]