from bisect import bisect_left

n, k = map(int, input().split())
A = list(map(int, input().split()))
L = A[: n // 3]
R = A[n // 3 :]


def f(A):
    res = [0]
    for a in A:
        le = len(res)
        for i in range(le):
            res.append(res[i] + a)
    res.sort()
    return res


L = f(L)
R = f(R)
l = -1 << 60
r = 1 << 60
while r - l > 1:
    m = (l + r) // 2
    cnt = 0
    for a in L:
        cnt += len(R) - bisect_left(R, m - a)
    if cnt < k:
        r = m
    else:
        l = m

print(l)