import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.PriorityQueue;
import java.util.Set;
import java.util.StringTokenizer;

public class Main {

	public static void main(String[] args) throws IOException {
//		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
//		StringTokenizer tk;
		Scanner scan = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);

		int n = scan.nextInt();

		int k = scan.nextInt();

		int arr[] = new int[n];

		for (int i = 0; i < n; i++)
			arr[i] = scan.nextInt();

		long count = 0;

		for (int i = 0; i < n; i++) {

			if (arr[i] % k == 0) {
				count += arr[i] / k;
				continue;
			}
			if (i != n - 1) {
				count += (k - arr[i] % k + arr[i]) / k;
				arr[i + 1] = Math.max(0, arr[i + 1] - (k - arr[i] % k));
				continue;

			}
			count += Math.ceil(arr[i] / (k * 1.0));
		}
		System.out.println(count);
	}

	static class Scanner {
		StringTokenizer st;
		BufferedReader br;

		public Scanner(InputStream s) {
			br = new BufferedReader(new InputStreamReader(s));
		}

		public String next() throws IOException {
			while (st == null || !st.hasMoreTokens())
				st = new StringTokenizer(br.readLine());
			return st.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public long nextLong() throws IOException {
			return Long.parseLong(next());
		}

		public String nextLine() throws IOException {
			return br.readLine();
		}

		public double nextDouble() throws IOException {
			String x = next();
			StringBuilder sb = new StringBuilder("0");
			double res = 0, f = 1;
			boolean dec = false, neg = false;
			int start = 0;
			if (x.charAt(0) == '-') {
				neg = true;
				start++;
			}
			for (int i = start; i < x.length(); i++)
				if (x.charAt(i) == '.') {
					res = Long.parseLong(sb.toString());
					sb = new StringBuilder("0");
					dec = true;
				} else {
					sb.append(x.charAt(i));
					if (dec)
						f *= 10;
				}
			res += Long.parseLong(sb.toString()) / f;
			return res * (neg ? -1 : 1);
		}

		public boolean ready() throws IOException {
			return br.ready();
		}

	}
}
