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

A_sum = [0]
[A_sum.append(A_sum[-1]+int(a)) for a in input().split()]

score = []
for r in range(1,N+1):
    for l in range(0,r):
        score.append(A_sum[r]-A_sum[l])

ans = 0
for i in range(40,-1,-1):
    count = 0
    score_a = []
    for j in score:
        if (j & (1<<i)):
            count += 1
            score_a.append(j)
    if count >= K:
        ans += (1<<i)
        score = [i for i in score_a]

print(ans)
