#include <bits/stdc++.h>
const int maxn = 2e5 + 1000;
int a[maxn];
using namespace std;
int main() {
  int n, c;
  long long ans = 0;
  cin >> n >> c;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  for (int i = 0; i < n - 1; i++) {
    if (a[i] < c && a[i]) {
      int t = a[i + 1] + a[i];
      if (t >= c) {
        ans += t / c;
        a[i + 1] = (a[i + 1] + a[i]) % c;
      } else
        a[i + 1] = 0, ans++;
    } else if (a[i] == c)
      a[i] = 0, ans++;
    else if (a[i] > c) {
      ans += a[i] / c;
      a[i] = a[i] % c;
      int t = a[i + 1] + a[i];
      if (t >= c) {
        ans += t / c;
        a[i + 1] = (a[i + 1] + a[i]) % c;
      } else
        ans++, a[i + 1] = 0;
    }
  }
  cout << ans + a[n - 1] / c;
}
