There is a toy building consisting of n towers. Each tower consists of several cubes standing on each other. The i-th tower consists of h_i cubes, so it has height h_i.

Let's define operation slice on some height H as following: for each tower i, if its height is greater than H, then remove some top cubes to make tower's height equal to H. Cost of one "slice" equals to the total number of removed cubes from all towers.

Let's name slice as good one if its cost is lower or equal to k (k ≥ n).

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Calculate the minimum number of good slices you have to do to make all towers have the same height. Of course, it is always possible to make it so.

Input

The first line contains two integers n and k (1 ≤ n ≤ 2 ⋅ 10^5, n ≤ k ≤ 10^9) — the number of towers and the restriction on slices, respectively.

The second line contains n space separated integers h_1, h_2, ..., h_n (1 ≤ h_i ≤ 2 ⋅ 10^5) — the initial heights of towers.

Output

Print one integer — the minimum number of good slices you have to do to make all towers have the same heigth.

Examples

Input

5 5
3 1 2 2 4


Output

2


Input

4 5
2 3 4 5


Output

2

Note

In the first example it's optimal to make 2 slices. The first slice is on height 2 (its cost is 3), and the second one is on height 1 (its cost is 4).
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.io.BufferedInputStream;
import java.util.ArrayList;
import java.io.FilterInputStream;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        ScanReader in = new ScanReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CMakeItEqual solver = new CMakeItEqual();
        solver.solve(1, in, out);
        out.close();
    }

    static class CMakeItEqual {
        public void solve(int testNumber, ScanReader in, PrintWriter out) {
            int n = in.scanInt();
            int k = in.scanInt();
            int arr[] = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = in.scanInt();
            }
            long pre[] = new long[n];
            Arrays.sort(arr);
            for (int i = 0; i < n; i++) pre[i] = arr[i];
            for (int i = 1; i < n; i++) pre[i] += pre[i - 1];
            int max_h = arr[n - 1];
            int equal = arr[0];
            int min_good = -1;


            AVLTree<pair> avlTree = new AVLTree<>();
            ArrayList<Long> arrayList = new ArrayList<>();
            for (int i = arr[0]; i <= max_h - 1; i++) {
                int lb = CodeX.lbound(arr, 0, n, i + 1);
                if (lb != n) {
                    long cost = pre[n - 1] - pre[lb - 1];
                    cost -= ((long) i * ((n - 1l) - lb + 1l));
                    avlTree.insert(new pair(cost, i));
                    arrayList.add(cost);
                    if (cost <= k) {
                        min_good = i;
                        break;
                    }
                } else {
                    throw new RuntimeException("This is never happed........");
                }
            }
            if (min_good == -1) {
                out.println(0);
                return;
            }
            if (min_good == equal) {
                out.println(1);
                return;
            }


            long ttt[] = new long[arrayList.size()];
            int t = 0;
            for (long ad : arrayList) {
                ttt[t++] = ad;
            }
            Arrays.sort(ttt);
            long ans = 0;
            int ii = 0;
            while (true) {
                ans++;
                long temp = ttt[ii] + k;
                int lb = CodeX.lbound(ttt, 0, ttt.length, temp + 1);
                if (lb != ttt.length) {
                    ii = lb - 1;
                } else {
                    ans++;
                    break;
                }
            }

            out.println(ans);


        }

        class pair implements Comparable<pair> {
            long cc;
            int index;

            public pair(long cc, int index) {
                this.cc = cc;
                this.index = index;
            }

            public int compareTo(pair o) {
                if (this.cc < o.cc) return -1;
                else if (this.cc == o.cc) return 0;
                return 1;
            }

        }

    }

    static class ScanReader {
        private byte[] buf = new byte[4 * 1024];
        private int INDEX;
        private BufferedInputStream in;
        private int TOTAL;

        public ScanReader(InputStream inputStream) {
            in = new BufferedInputStream(inputStream);
        }

        private int scan() {
            if (INDEX >= TOTAL) {
                INDEX = 0;
                try {
                    TOTAL = in.read(buf);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                if (TOTAL <= 0) return -1;
            }
            return buf[INDEX++];
        }

        public int scanInt() {
            int I = 0;
            int n = scan();
            while (isWhiteSpace(n)) n = scan();
            int neg = 1;
            if (n == '-') {
                neg = -1;
                n = scan();
            }
            while (!isWhiteSpace(n)) {
                if (n >= '0' && n <= '9') {
                    I *= 10;
                    I += n - '0';
                    n = scan();
                }
            }
            return neg * I;
        }

        private boolean isWhiteSpace(int n) {
            if (n == ' ' || n == '\n' || n == '\r' || n == '\t' || n == -1) return true;
            else return false;
        }

    }

    static class AVLTree<T extends Comparable<? super T>> {
        private Node<T> root;
        private boolean multi;

        public AVLTree() {
            this.root = null;
            this.multi = false;
        }

        public AVLTree(boolean multi) {
            this.root = null;
            this.multi = multi;
        }

        public void insert(T data, int... count) {
            if (count.length == 0) root = insert(data, root, 1);
            else {
                if (count[0] > 0) root = insert(data, root, count[0]);
            }
        }

        private Node<T> insert(T data, Node<T> tempRoot, int count) {
            if (tempRoot == null) {
                if (!multi) {

                    return new Node<>(data);
                } else {

                    return new Node<>(data, count);
                }
            }


            int compartor = data.compareTo(tempRoot.data);
            if (compartor < 0) {
                tempRoot.left = insert(data, tempRoot.left, count);
            } else if (compartor > 0) {
                tempRoot.right = insert(data, tempRoot.right, count);
            } else {
                if (multi) {
                    tempRoot.count += count;
                }
            }


            tempRoot.leftcount = getLeftCount(tempRoot.left) + getRightCount(tempRoot.left) + getCount(tempRoot.left);
            tempRoot.rightcount = getLeftCount(tempRoot.right) + getRightCount(tempRoot.right) + getCount(tempRoot.right);


            tempRoot.height = Math.max(Hieght(tempRoot.left), Hieght(tempRoot.right)) + 1;


            long diff = getBalence(tempRoot);

            if (diff > 1) {
                if (data.compareTo(tempRoot.left.data) < 0) {
                    return rotateRight(tempRoot);
                } else {
                    tempRoot.left = rotateLeft(tempRoot.left);
                    return rotateRight(tempRoot);
                }
            } else if (diff < -1) {
                if (data.compareTo(tempRoot.right.data) > 0) {
                    return rotateLeft(tempRoot);
                } else {
                    tempRoot.right = rotateRight(tempRoot.right);
                    return rotateLeft(tempRoot);
                }
            }

            return tempRoot;


        }

        public Node<T> rotateRight(Node<T> node) {
            Node<T> x = node.left;
            Node<T> t2 = x.right;


            x.right = node;
            node.left = t2;


            node.height = Math.max(Hieght(node.right), Hieght(node.left)) + 1;
            x.height = Math.max(Hieght(x.left), Hieght(x.right)) + 1;


            node.leftcount = getLeftCount(node.left) + getRightCount(node.left) + getCount(node.left);
            node.rightcount = getLeftCount(node.right) + getRightCount(node.right) + getCount(node.right);


            x.leftcount = getLeftCount(x.left) + getRightCount(x.left) + getCount(x.left);
            x.rightcount = getLeftCount(x.right) + getRightCount(x.right) + getCount(x.right);

            return x;

        }

        public Node<T> rotateLeft(Node<T> node) {
            Node<T> x = node.right;
            Node<T> t2 = x.left;


            x.left = node;
            node.right = t2;


            node.height = Math.max(Hieght(node.right), Hieght(node.left)) + 1;
            x.height = Math.max(Hieght(x.left), Hieght(x.right)) + 1;


            node.leftcount = getLeftCount(node.left) + getRightCount(node.left) + getCount(node.left);
            node.rightcount = getLeftCount(node.right) + getRightCount(node.right) + getCount(node.right);


            x.leftcount = getLeftCount(x.left) + getRightCount(x.left) + getCount(x.left);
            x.rightcount = getLeftCount(x.right) + getRightCount(x.right) + getCount(x.right);

            return x;

        }

        public long getLeftCount(Node<T> node) {
            if (node == null) return 0;
            return node.leftcount;
        }

        public long getRightCount(Node<T> node) {
            if (node == null) return 0;
            return node.rightcount;
        }

        public long getCount(Node<T> node) {
            if (node == null) return 0;
            return node.count;
        }

        long getBalence(Node<T> node) {
            if (node == null)
                return 0;

            return Hieght(node.left) - Hieght(node.right);
        }

        public long Hieght(Node<T> Node) {
            if (Node == null) return 0;
            else return Node.height;
        }

        public class Node<T> {
            T data;
            long height;
            Node<T> left;
            Node<T> right;
            long leftcount;
            long rightcount;
            long count;

            public Node(T data) {
                this.data = data;
                this.height = 1;
                this.left = null;
                this.right = null;
                this.leftcount = 0;
                this.rightcount = 0;
                this.count = 1;
            }

            public Node(T data, int count) {
                this.data = data;
                this.height = 1;
                this.left = null;
                this.right = null;
                this.leftcount = 0;
                this.rightcount = 0;
                this.count = count;
            }

        }

    }

    static class CodeX {
        public static int lbound(long array[], int l, int h, long x) {
            while (l < h) {
                int mid = (l + h) / 2;
                if (array[mid] >= x) h = mid;
                else l = mid + 1;
            }
            return l;
        }

        public static int lbound(int array[], int l, int h, int x) {
            while (l < h) {
                int mid = (l + h) / 2;
                if (array[mid] >= x) h = mid;
                else l = mid + 1;
            }
            return l;
        }

    }
}

