I submitted this code, and it was accepted, though if n=2 and k=5, the answer is 1, which is impossible

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

public class ch1 {
    public static void main(String args[]) throws ArithmeticException{
        Scanner in =new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        long N = in.nextLong();
        long K = in.nextLong();
            N=2*N;
            if(N==2) out.print(2);
            else if(N%K==0) out.print(N/K);
            else out.print(N/K+1);

        out.flush();
        in.close();
        out.close();
    }
}