from bisect import *

N, K = map(int, input().split())
A = list(map(int, input().split()))
if N == 1:
    print(sorted([0, A[0]], reverse=True)[K - 1])
    exit()
    
B, C = A[:N//2], A[N//2:]
N, M = len(B), len(C)
N2, M2 = 1 << N, 1 << M
L1 = []
for s in range(N2):
    val = 0
    for i in range(N):
        if (s >> i) & 1:
            val += B[i]
    L1.append(val)
    
L2 = []
for s in range(M2):
    val = 0
    for i in range(M):
        if (s >> i) & 1:
            val += C[i]
    L2.append(val) 
L2.sort()

def check(m):
    cnt = 0
    for a in L1:
        cnt += M2 - bisect_left(L2, m - a)
    return cnt >= K
        
            
yes = -10 ** 12
no = 10 ** 12
while no - yes != 1:
    mid = (yes + no)//2
    if check(mid):
        yes = mid
    else:
        no = mid
        
print(yes)