import sys
#input = sys.stdin.readline #文字列につけてはダメ
#input = sys.stdin.buffer.readline #文字列につけてはダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
from collections import defaultdict 
#from collections import deque
#import copy
#import math
#from functools import lru_cache
#MOD = pow(10,9) + 7
#MOD = 998244353


def main():
    N,M = map(int,input().split())
    A = list(map(int,input().split()))

    def check(x):
        amari = 0
        for a in A:
            if a + amari < x*M:
                return False
            amari = (a + amari - x*M)
        return True

    ok = 0
    ng = pow(10,9) + 100
    while abs(ok-ng) > 1:
        mid = (ok+ng)//2
        if check(mid):
            ok = mid
        else:
            ng = mid
    print(ok)

if __name__ == '__main__':
    main()