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

def check(x):
    a = 0
    b = 0
    for i in range(N):
        tmp = A[i] + b - x
        if tmp < 0:
            tmp2 = - (tmp // (i + 1))
            a += tmp2
            b += tmp2 * (i + 1)
        if a > K:
            return False
    return True

lb = 0
ub = A[0] + K + 1
while ub - lb > 1:
    mid = (ub + lb) // 2
    if check(mid):
        lb = mid
    else:
        ub = mid
print(lb)