n, k = list(map(int, input().split()))
a = list(map(int, input().split()))
b = []
c = []
i = 0
while i < n*(n-1)//2:
    m = n - i
    for j in range(i+1):
        c = a[j:j + m]
        if sum(c) != 0:
            b.append(sum(c))
    i += 1
d = sorted(b, reverse=True)
for i in range(k):
    c.append(d[i])

ans = d[0]
for i in range(k):
    if i+1 == len(c):
        break
    ans = ans & c[i+1]
print(ans)