from collections import defaultdict, deque, Counter
from heapq import heapify, heappop, heappush
import math
from copy import deepcopy
from itertools import combinations, permutations, product, combinations_with_replacement
from bisect import bisect_left, bisect_right

import sys

def input():
    return sys.stdin.readline().rstrip()
def getN():
    return int(input())
def getNM():
    return map(int, input().split())
def getList():
    return list(map(int, input().split()))
def getListGraph():
    return list(map(lambda x:int(x) - 1, input().split()))
def getArray(intn):
    return [int(input()) for i in range(intn)]

mod = 10 ** 9 + 7
MOD = 998244353
# sys.setrecursionlimit(10000000)
inf = float('inf')
eps = 10 ** (-15)
dy = [0, 1, 0, -1]
dx = [1, 0, -1, 0]

#############
# Main Code #
#############

# 効率的な方法
# 一個消費して上位のものを生成する
# minの最大値を求める
# 二分探索する

N, M = getNM()
A = getList()

def f(x):
    stone = 0
    for i in range(N):
        stone += A[i] - x
        if stone < 0:
            return False
    return True

ok, ng = 0, 10 ** 18
while abs(ng - ok) > 1:
    mid = (ok + ng) // 2
    if f(mid):
        ok = mid
    else:
        ng = mid

print(ok // M)