#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using mint = modint998244353;

bool func(vector<ll> &a, ll n, ll m, ll k) {
  ll s = 0;
  ll t = m * k;
  bool res = true;
  for (int i = 0; i < n; i++) {
    s += a[i];
    if (s < t) {
      res = false;
      break;
    }
    t += m * k;
  }
  return res;
}
int main() {
  ll n, m; cin >> n >> m;
  vector<ll> a(n);
  for (auto &x: a) cin >> x;

  ll ok = 0;
  ll ng = 1000000001;
  while (ng - ok > 1) {
    ll k = (ok + ng) / 2;
    if (func(a, n, m, k)) ok = k;
    else ng = k;
  }
  cout << ok << endl;
  return 0;
}