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.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Arrays;
import java.util.Deque;
import java.util.HashMap;
import java.util.InputMismatchException;
import java.util.LinkedList;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.lang.Math;
import java.math.BigInteger; 

public class Main
{
	static long t,l,r,v,n,k,x,y,res=0,len,pow;
	static BigInteger tot,df,a,b,tmp;
	static StringBuilder sb1,sb2;
	static String s;

	public static void main(String[] args)throws IOException
	{
		MainFastScan scanner = new MainFastScan();
		MainFastPrint printer = new MainFastPrint();
		
		long tot,frnd,cur,nw;
		
		tot = scanner.nextLong();
		frnd = scanner.nextLong();
		cur = scanner.nextLong();
		nw = scanner.nextLong();
		
		
		cur += nw;
		
		long tt = 0;
		
		if(cur%frnd!=0) tt = cur/frnd + 1;
		else tt = cur/frnd;
		
		//System.out.println(tt);
		
		if(tt*frnd>tot) res = -1;
		else res = tt;
		
		
		printer.printLine(Long.toString(res));
		
		/*t = scanner.nextLong();
		for(int cs = 1; cs<=t; cs++)
		{
			n = scanner.nextLong();
			k = scanner.nextLong();
			
			k = Math.min(k, n-k);
			res = 1;
			long tmp = n;
			for(int i=1; i<=k; i++)
			{
				res *= tmp--;
				res /= i;
				if(res>=1000003) res %= 1000003;
			}
			printer.printLine("Case " + cs + ": " + Long.toString(res));
		}	*/	
		printer.close();

	}
}





class MainFastPrint
{
	private final BufferedWriter bw;
	public MainFastPrint(){bw=new BufferedWriter(new OutputStreamWriter(System.out));}
	public void print(String str)throws IOException{bw.append(str);}
	public void printLine(String str)throws IOException{print(str); bw.append("\n");}
	public void close()throws IOException{bw.close();}
}

class MainFastScan
{
	private byte[] buf=new byte[1024];
	private int index;
	private InputStream in;
	private int total;
	public MainFastScan()
	{
		in=System.in;
	}
	public int scan()throws IOException
	{
		if(total<0)
			throw new InputMismatchException();
		if(index>=total)
		{
			index=0;
			total=in.read(buf);
			if(total<=0)
				return -1;
		}
		return buf[index++];
	}
	public int nextInt()throws IOException
	{
		int integer=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')
			{
				integer*=10;
				integer+=n-'0';
				n=scan();
			}
			else throw new InputMismatchException();
		}
		return neg*integer;
	}

	public long nextLong()throws IOException
	{
		long res=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')
			{
				res *= 10;
				res += n-'0';
				n=scan();
			}
			else throw new InputMismatchException();
		}
		return neg*res;
	}

	public double nextDouble()throws IOException
	{
		double doub=0;
		int n=scan();
		while(isWhiteSpace(n)) n=scan();
		int neg=1;
		if(n=='-')
		{
			neg=-1;
			n=scan();
		}
		while(!isWhiteSpace(n)&&n!='.')
		{
			if(n>='0'&&n<='9')
			{
				doub*=10;
				doub+=n-'0';
				n=scan();
			}
			else throw new InputMismatchException();
		}
		if(n=='.')
		{
			n=scan();
			double temp=1;
			while(!isWhiteSpace(n))
			{
				if(n>='0'&&n<='9')
				{
					temp/=10;
					doub+=(n-'0')*temp;
					n=scan();
				}
				else throw new InputMismatchException();
			}
		}
		return doub*neg;
	}
	public String nextWord()throws IOException
	{
		StringBuilder sb=new StringBuilder();
		int n=scan();
		while(isWhiteSpace(n)) n=scan();
		while(!isWhiteSpace(n))
		{
			sb.append((char)n);
			n=scan();
		}
		return sb.toString();
	}
	public String nextLine()throws IOException
	{
		StringBuilder sb=new StringBuilder();
		int n=scan();
		while(isWhiteSpaceLine(n)) n=scan();
		while(!isWhiteSpaceLine(n))
		{
			sb.append((char)n);
			n=scan();
		}
		return sb.toString();
	}
	private boolean isWhiteSpace(int n)
	{
		if(n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1)
			return true;
		return false;
	}
	private boolean isWhiteSpaceLine(int n)
	{
		if(n=='\n'||n=='\r'||n=='\t'||n==-1)
			return true;
		return false;
	}
}