Petya is having a party soon, and he has decided to invite his n friends.

He wants to make invitations in the form of origami. For each invitation, he needs two red sheets, five green sheets, and eight blue sheets. The store sells an infinite number of notebooks of each color, but each notebook consists of only one color with k sheets. That is, each notebook contains k sheets of either red, green, or blue.

Find the minimum number of notebooks that Petya needs to buy to invite all n of his friends.

Input

The first line contains two integers n and k (1≤ n, k≤ 10^8) — the number of Petya's friends and the number of sheets in each notebook respectively.

Output

Print one number — the minimum number of notebooks that Petya needs to buy.

Examples

Input


3 5


Output


10


Input


15 6


Output


38

Note

In the first example, we need 2 red notebooks, 3 green notebooks, and 5 blue notebooks.

In the second example, we need 5 red notebooks, 13 green notebooks, and 20 blue notebooks.
'''
n - number of friends
k - number of sheets in notebook

one friend needs 2 red, 5 green and 8 blue sheets


on the first example:
    n = 3, k = 5
    
    Petya needs 6 red, 15 green and 24 blue sheets
    if each notebook contains 5 sheets, then he needs 2 red, 3 green and 5 blue notebooks
    or (n*redNeeded)/k + (n*greenNeeded)/k + (n*blueNeeded)/k
    but (n*redNeeded)/k = (3*2)/5 which will return 1. so we need to check for reminder and if it exists, add 1 to the sum
    on the other hand, let's imagine situation like this:
        n = 3, k = 7
        in this case => (n*redNeeded)/k = (3*2)/7 which will return 0, but this means, that one notebook is enough and we would have extra sheets.
        so we also should check for this case and if true, also add 1 to the sum
        
     at the end print the sum 
'''

n,k = map(int, input().split())

red = n*2
green = n*5
blue = n*8

ans = red//k + green//k + blue//k

if red%k > 0 or red//k == 0:
    ans +=1
if green%k > 0 or green//k == 0:
    ans +=1
if blue%k > 0 or blue//k == 0:
    ans +=1


print (ans)