A. Petya and Origami
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

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 $k$ ($1\leq n, k\leq 10^8$) — 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.