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.io.*;
import java.util.*; // тут лежат все коллекции, Random

// имя начинается с двух подчеркиваний, чтобы был первым в списке (он сортится по алфавиту)
public class __Solution {

    // определяет, запускается решение "дома" или на CF/timus
    static final boolean ONLINE_JUDGE = System.getProperty("ONLINE_JUDGE") != null;

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

    BufferedReader in;
    PrintWriter out;
    StringTokenizer tok;

    void init() throws FileNotFoundException {
        // иницилизация потоков вводилок/выводилок
        // System.in/System.out - стандартные потоки ввода/вывода на консоль

        if (ONLINE_JUDGE) {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
        } else {
            in = new BufferedReader(new FileReader("input.txt"));
            out = new PrintWriter("output.txt");
        }

        tok = new StringTokenizer("");
    }

    void run() {
        try {
            long timeStart = System.currentTimeMillis();

            init();
            solve();

            out.close();

            long timeEnd = System.currentTimeMillis();
            System.err.println("Time = " + (timeEnd - timeStart));
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(-1);
        }
    }

    // чтение строки вернет null, если ничего не осталось
    String readLine() throws IOException {
        return in.readLine();
    }

    // содержит символы, являющиеся "разделителями ввода"
    // по умолчанию это пробел (перевод строки автоматом учитывается)
    String delimiter = " ";

    String readString() throws IOException {
        while (!tok.hasMoreTokens()) {
            String nextLine = readLine();
            if (null == nextLine) return null;

            tok = new StringTokenizer(nextLine);
        }

        return tok.nextToken(delimiter);
    }

    int readInt() throws IOException {
        return Integer.parseInt(readString());
    }

    long readLong() throws IOException {
        return Long.parseLong(readString());
    }
    int min (int a, int b){
        return (a < b) ? a : b;
    }
    int min (int a, int b, int c){
        return min(min(a, b), c);
    }
    // тут мы будем писать основное решение


    void solve() throws IOException {
        long n = readLong();
        long m = readLong();
        long k = readLong();
        long l = readLong();

        long upper = n/m;
        long lower = (l+k)/m;
        if ((l+k) % m != 0) lower++;
        if (lower > upper) out.println(-1);
        else out.println(lower);
    }
}

