Enough is enough. Too many times it happened that Vasya forgot to dispose of garbage and his apartment stank afterwards. Now he wants to create a garbage disposal plan and stick to it.

For each of next n days Vasya knows a_i — number of units of garbage he will produce on the i-th day. Each unit of garbage must be disposed of either on the day it was produced or on the next day. Vasya disposes of garbage by putting it inside a bag and dropping the bag into a garbage container. Each bag can contain up to k units of garbage. It is allowed to compose and drop multiple bags into a garbage container in a single day.

Being economical, Vasya wants to use as few bags as possible. You are to compute the minimum number of bags Vasya needs to dispose of all of his garbage for the given n days. No garbage should be left after the n-th day.

Input

The first line of the input contains two integers n and k (1 ≤ n ≤ 2⋅10^5, 1 ≤ k ≤ 10^9) — number of days to consider and bag's capacity. The second line contains n space separated integers a_i (0 ≤ a_i ≤ 10^9) — the number of units of garbage produced on the i-th day.

Output

Output a single integer — the minimum number of bags Vasya needs to dispose of all garbage. Each unit of garbage should be disposed on the day it was produced or on the next day. No garbage can be left after the n-th day. In a day it is allowed to compose and drop multiple bags.

Examples

Input

3 2
3 2 1


Output

3


Input

5 1
1000000000 1000000000 1000000000 1000000000 1000000000


Output

5000000000


Input

3 2
1 0 1


Output

2


Input

4 4
2 8 4 1


Output

4

import java.util.*;
import java.io.*;

public class D {

	static final boolean stdin = true;
	static final String filename = "";
	static FastScanner br;
	static PrintWriter pw;

	public static void main(String[] args) throws IOException {

		if (stdin) {
			br = new FastScanner();
			pw = new PrintWriter(new OutputStreamWriter(System.out));
		} else {
			br = new FastScanner(filename + ".in");
			pw = new PrintWriter(new FileWriter(filename + ".out"));
		}

		Solver solver = new Solver();
		solver.solve(br, pw);
		pw.close();
	}

	static class Solver {
		static long mod = (long) (1e9);

		public void solve(FastScanner br, PrintWriter pw) throws IOException {
			int n = br.ni();
			int k = br.ni();
			int[] in = br.nia(n);
			long next = 0;
			long out = 0;
			for (int i = 0; i < n - 1; i++) {
				if (next > 0) {
					if (next % k == 0) {
						out += next / k;
						next = 0;
					} else {
						out += 1 + next / k;
						next -= k*(1 + next / k);
					}
				}
				next += in[i];
				next = Math.max(next, 0);
				//pw.println(out + " " + next);
			}
			next += in[n - 1];
			out += next / k;
			out += next % k == 0 ? 0 : 1;
			pw.println(out);
		}

		static long gcd(long a, long b) {
			if (a > b)
				return gcd(b, a);
			if (a == 0)
				return b;
			return gcd(b % a, a);
		}

		static long lcm(long a, long b) {
			return a * (b / gcd(a, b));
		}

		static long pow(long a, long b) {
			if (b == 0)
				return 1L;
			long val = pow(a, b / 2);
			if (b % 2 == 0)
				return val * val % mod;
			else
				return val * val % mod * a % mod;
		}

	}

	static class Point implements Comparable<Point> {
		int a;
		int b;

		Point(int a, int b) {
			this.a = a;
			this.b = b;
		}

		@Override
		public int compareTo(Point o) {
			return this.a - o.a;
		}

		public boolean equals(Object obj) {
			if (obj instanceof Point) {
				Point other = (Point) obj;
				return a == other.a && b == other.b;
			}
			return false;
		}

		public int hashCode() {
			return 65536 * a + b + 4733 * 0;
		}

	}

	public static class FastScanner {
		BufferedReader br;
		StringTokenizer st;

		public FastScanner(String s) {
			try {
				br = new BufferedReader(new FileReader(s));
			} catch (FileNotFoundException e) {
				e.printStackTrace();
			}
		}

		public FastScanner() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		ArrayList<Integer>[] ng(int n, int e) {
			ArrayList<Integer>[] adj = new ArrayList[n];
			for (int i = 0; i < n; i++) {
				adj[i] = new ArrayList<Integer>();
			}
			for (int i = 0; i < e; i++) {
				int a = ni() - 1;
				int b = ni() - 1;
				adj[a].add(b);
				adj[b].add(a);
			}
			return adj;
		}

		Integer[] nIa(int n) {
			Integer[] arr = new Integer[n];
			for (int i = 0; i < n; i++) {
				arr[i] = ni();
			}
			return arr;
		}

		int[] nia(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = ni();
			}
			return arr;
		}

		Long[] nLa(int n) {
			Long[] arr = new Long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nl();
			}
			return arr;
		}

		long[] nla(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nl();
			}
			return arr;
		}

		String[] nsa(int n) {
			String[] arr = new String[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nt();
			}
			return arr;
		}

		String nt() {
			while (st == null || !st.hasMoreElements()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int ni() {
			return Integer.parseInt(nt());
		}

		long nl() {
			return Long.parseLong(nt());
		}

		double nd() {
			return Double.parseDouble(nt());
		}

	}
}