source_code: 
  import java.util.Scanner;
  
  public class origami {
  	public static void main(String args[]){
  		Scanner input = new Scanner(System.in);
  		double n = input.nextInt();
  		double k = input.nextInt();
  		double red = 0;
  		double green = 0;
  		double blue = 0;
  		double ans = 0;
  		red = (2 * n) / k;
  		green = (5 * n) / k;
  		blue = (8 * n) / k;
  
  		double red1 = Math.ceil(red) ;
  		double green1 = Math.ceil(green);
  		double blue1 = Math.ceil(blue);
  
  		ans+=red1;
  		ans+=green1;
  		ans+=blue1;
  		Double answer = new Double(ans);
  		int finished = answer.intValue();
  		System.out.println(finished);
  	}
  }
  