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


public class D {

    static class Pair<U extends Comparable<U>, V extends Comparable<V>>
            implements Comparable<Pair<U,V>>{

        public U a;
        public V b;

        private Pair(U a, V b) {
            this.a = a;
            this.b = b;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o)
                return true;
            if (o == null || getClass() != o.getClass())
                return false;

            Pair<?, ?> pair = (Pair<?, ?>) o;
            if (!a.equals(pair.a))
                return false;
            return b.equals(pair.b);
        }

        @Override
        public int hashCode() {
            return 31 * a.hashCode() + b.hashCode();
        }

        @Override
        public String toString() {
            return "(" + a + ", " + b + ")";
        }

        @Override
        public int compareTo(Pair<U, V> o) {
            if(this.a.equals(o.a)){
                return getV().compareTo(o.getV());
            }
            return getU().compareTo(o.getU());
        }
        private U getU() {
            return a;
        }
        private V getV() {
            return b;
        }
    }


    static BufferedReader inp = new BufferedReader(new InputStreamReader(System.in));
    static BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out));

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

        String[] s1 = inp.readLine().split(" ");
        int day = Integer.parseInt(s1[0]);
        long k = Integer.parseInt(s1[1]);

        long restSpace = 0;

        long ans = 0;


        s1 = inp.readLine().split(" ");

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

            long a = Long.parseLong(s1[i]);

            a-=restSpace;

            restSpace = 0;

            if(a>0) {
                long rem = a % k;
                if(rem==0){
                    ans+=a/k;
                }
                else {
                    ans+=a/k +1;
                    restSpace = k-rem;
                }
            }

        }

        out.write(ans+"\n");

        out.flush();

    }


    static void print(int[] array){
        for(int j=0;j<array.length;j++){
            System.out.print(array[j]+" ");
        }
        System.out.println();
    }
    static void print(int[][] array){
        for(int i=0;i< array.length;i++) {
            for (int j = 0; j < array[0].length; j++) {
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }
    }
    static void print(boolean[] array){
        for(int j=0;j<array.length;j++){
            System.out.print(array[j]+" ");
        }
        System.out.println();
    }
    static void print(boolean[][] array){
        for(int i=0;i< array.length;i++) {
            for (int j = 0; j < array[0].length; j++) {
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }
    }
    static void print(long[] array){
        for(int j=0;j<array.length;j++){
            System.out.print(array[j]+" ");
        }
        System.out.println();
    }
    static void print(long[][] array){
        for(int i=0;i< array.length;i++) {
            for (int j = 0; j < array[0].length; j++) {
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }
    }
    static void print(String[] array){
        for(int j=0;j<array.length;j++){
            System.out.print(array[j]+" ");
        }
        System.out.println();
    }
    static void print(String[][] array){
        for(int i=0;i< array.length;i++) {
            for (int j = 0; j < array[0].length; j++) {
                System.out.print(array[i][j] + " ");
            }
            System.out.println();
        }
    }
}