n, m = map(int,input().split())
a = list(map(int,input().split()))
import copy
def check(x, a):
    for i in range(n):
        if a[i] < m * x:
            return False
        elif i < n - 1:
            a[i + 1] += a[i] - m * x
    return True

ok = 0
ng = 10 ** 9 + 3

while abs(ok - ng) > 1:
    A = copy.copy(a)
    mid = (ok + ng) // 2
    if check(mid, A):
        ok = mid
    else:
        ng = mid
print(ok)