/* -*- coding: utf-8 -*-
 *
 * 1808.cc:  No.1808 Fullgold Alchemist - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 200000;
const int INF = 1 << 30;

/* typedef */

typedef long long ll;

/* global variables */

int as[MAX_N];

/* subroutines */

/* main */

int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; i++) scanf("%d", as + i);

  int minav = INF;
  for (int i = n - 1; i >= 0;) {
    int j = i;
    ll sum = 0;
    while (j >= 0 && sum <= (ll)as[j] * (i - j))
      sum += as[j--];

    int av = sum / (i - j);
    minav = min(minav, av);

    i = j;
  }

  printf("%d\n", minav / m);
  return 0;
}