Ivan is collecting coins. There are only N different collectible coins, Ivan has K of them. He will be celebrating his birthday soon, so all his M freinds decided to gift him coins. They all agreed to three terms: 

  * Everyone must gift as many coins as others.
  * All coins given to Ivan must be different.
  * Not less than L coins from gifts altogether, must be new in Ivan's collection.



But his friends don't know which coins have Ivan already got in his collection. They don't want to spend money so they want to buy minimum quantity of coins, that satisfy all terms, irrespective of the Ivan's collection. Help them to find this minimum number of coins or define it's not possible to meet all the terms.

Input

The only line of input contains 4 integers N, M, K, L (1 ≤ K ≤ N ≤ 10^{18}; 1 ≤ M,    L ≤ 10^{18}) — quantity of different coins, number of Ivan's friends, size of Ivan's collection and quantity of coins, that must be new in Ivan's collection.

Output

Print one number — minimal number of coins one friend can gift to satisfy all the conditions. If it is impossible to satisfy all three conditions print "-1" (without quotes).

Examples

Input

20 15 2 3


Output

1

Input

10 11 2 4


Output

-1

Note

In the first test, one coin from each friend is enough, as he will be presented with 15 different coins and 13 of them will definitely be new.

In the second test, Ivan has 11 friends, but there are only 10 different coins. So all friends can't present him different coins.
import java.util.*;
import java.io.*;

public class Birthday {
    PrintWriter out;
    StringTokenizer st;
    BufferedReader br;
    final int imax = Integer.MAX_VALUE, imin = Integer.MIN_VALUE;
    final int mod = 1000000007;

    void solve() throws Exception {
        int t = 1;
//        t = ni();
        for (int ii = 0; ii < t; ii++) {
            long n= nl(), m= nl(), k= nl(), l= nl();

            long min= (k+l)/m+ ((k+l)%m== 0? 0: 1);
            if(min*m> n) out.println(-1);
            else out.println(min);
        }
    }

    public static void main(String[] args) throws Exception {
        new Birthday().run();
    }

    void run() throws Exception {
        if (System.getProperty("ONLINE_JUDGE") == null) {
            File file = new File("C:\\college\\CodeForces\\inputf.txt");
            br = new BufferedReader(new FileReader(file));
            out = new PrintWriter("C:\\college\\CodeForces\\outputf.txt");
        } else {
            out = new PrintWriter(System.out);
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        long ss = System.currentTimeMillis();
        st = new StringTokenizer("");
        while (true) {
            solve();
            String s = br.readLine();
            if (s == null) break;
            else st = new StringTokenizer(s);
        }
        //out.println(System.currentTimeMillis()-ss+"ms");
        out.flush();
    }

    void read() throws Exception {
        st = new StringTokenizer(br.readLine());
    }

    int ni() throws Exception {
        if (!st.hasMoreTokens()) read();
        return Integer.parseInt(st.nextToken());
    }

    char nc() throws Exception {
        if (!st.hasMoreTokens()) read();
        return st.nextToken().charAt(0);
    }

    String nw() throws Exception {
        if (!st.hasMoreTokens()) read();
        return st.nextToken();
    }

    long nl() throws Exception {
        if (!st.hasMoreTokens()) read();
        return Long.parseLong(st.nextToken());
    }

    int[] ni(int n) throws Exception {
        int[] ret = new int[n];
        for (int i = 0; i < n; i++) ret[i] = ni();
        return ret;
    }

    long[] nl(int n) throws Exception {
        long[] ret = new long[n];
        for (int i = 0; i < n; i++) ret[i] = nl();
        return ret;
    }

    double nd() throws Exception {
        if (!st.hasMoreTokens()) read();
        return Double.parseDouble(st.nextToken());
    }

    String ns() throws Exception {
        String s = br.readLine();
        return s.length() == 0 ? br.readLine() : s;
    }

    void print(int[] arr) {
        for (int i : arr) out.print(i + " ");
        out.println();
    }

    void print(long[] arr) {
        for (long i : arr) out.print(i + " ");
        out.println();
    }

    void print(int[][] arr) {
        for (int[] i : arr) {
            for (int j : i) out.print(j + " ");
            out.println();
        }
    }

    void print(long[][] arr) {
        for (long[] i : arr) {
            for (long j : i) out.print(j + " ");
            out.println();
        }
    }

    long add(long a, long b) {
        if (a + b >= mod) return (a + b) - mod;
        else return a + b >= 0 ? a + b : a + b + mod;
    }

    long mul(long a, long b) {
        return (a * b) % mod;
    }

    void print(boolean b) {
        if (b) out.println("YES");
        else out.println("NO");
    }

    long binExp(long base, long power) {
        long res = 1l;
        while (power != 0) {
            if ((power & 1) == 1) res = mul(res, base);
            base = mul(base, base);
            power >>= 1;
        }
        return res;
    }

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

    // strictly smaller on left
    void stack_l(int[] arr, int[] left) {
        Stack<Integer> stack = new Stack<>();
        for (int i = 0; i < arr.length; i++) {
            while (!stack.isEmpty() && arr[stack.peek()] >= arr[i]) stack.pop();
            if (stack.isEmpty()) left[i] = -1;
            else left[i] = stack.peek();
            stack.push(i);
        }
    }

    // strictly smaller on right
    void stack_r(int[] arr, int[] right) {
        Stack<Integer> stack = new Stack<>();
        for (int i = arr.length - 1; i >= 0; i--) {
            while (!stack.isEmpty() && arr[stack.peek()] >= arr[i]) stack.pop();
            if (stack.isEmpty()) right[i] = arr.length;
            else right[i] = stack.peek();
            stack.push(i);
        }
    }

    private void sort(int[] arr) {
        List<Integer> list = new ArrayList<>();
        for (int i : arr) list.add(i);
        Collections.sort(list);
        for (int i = 0; i < arr.length; i++) arr[i] = list.get(i);
    }
}