n, m = map(int, input().split())
a = list(map(int, input().split()))
l = 0
r = 10 ** 9 + 1
while r - l > 1:
    c = (l + r) // 2
    carry = 0
    for x in a:
        x += carry
        if x < m * c:
            break
        carry = x - m * c
    else:
        l = c
        continue
    r = c
print(l)