N, M = map(int, input().split())
A = tuple(map(int, input().split()))


def isOK(x):
    cur = 0
    for a in A:
        cur += a - x
        if cur < 0:
            return False
    return True


l, r = 0, 10 ** 18
while r - l > 1:
    m = (r + l) // 2
    if isOK(m * M):
        l = m
    else:
        r = m
print(l)