import sys
input = sys.stdin.readline
from bisect import bisect_left

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

if N==1:
    if K==2:
        print(0)
    else:
        print(A[0])
    exit()

A.sort()

B=A[:N//2]
C=A[N//2:]

X=[0]

for b in B:
    Y=[]
    for x in X:
        Y.append(x+b)

    X=X+Y

X2=[0]
for b in C:
    Y=[]
    
    for x in X2:
        Y.append(x+b)

    X2=X2+Y

X.sort()
X2.sort()

OK=-40*10**9
NG=40*10**9

while OK<NG-1:
    mid=(OK+NG)//2

    count=0
    #count+=len(X2)-bisect_left(X2,mid)
    #count+=len(X)-bisect_left(X,mid)
    for x in X:
        count+=len(X2)-bisect_left(X2,mid-x)

    #print(mid,count)

    if count>=K:
        OK=mid
    else:
        NG=mid

print(OK)