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.

"""
def three_numbers():
    numbers = list(map(int, input().split(sep=' ')))
    m = max(numbers)
    for i in numbers:
        if i != m:
            print(m - i, end=' ')


def gen_and_card_game():
    card = input()
    my_cards = list(input().split(sep=' '))
    for i in my_cards:
        if i[0] == card[0] or i[1] == card[1]:
            print('YES')
            break
    else:
        print('NO')


def kazak_vus_and_contest():
    a, b, c = map(int, input().split(sep=' '))
    if a - b <= 0 and a - c <= 0:
        print('YES')
    else:
        print('NO')


def like_A():
    st = input()
    count_a = 0
    for i in st:
        if i == 'a':
            count_a += 1
    if count_a > len(st) - count_a:
        print(len(st))
    else:
        print(count_a + count_a - 1)


def three_piece_candies():
    n = int(input())
    for i in range(n):
        a, b, c = map(int, input().split(sep=' '))
        print((a + b + c) // 2)


def re_encryption():
    n = int(input())
    encryption = input()
    decipherment = ''
    k = 0
    while 0 != n:
        k += 1
        n -= k
    for i in range(1, k + 1):
        decipherment += encryption[0]
        encryption = encryption[i:]
    print(decipherment)


def two_type_burgers():
    n = int(input())
    for i in range(n):
        a, b, c = map(int, input().split(sep=' '))
        p_b, p_c = map(int, input().split(sep=' '))
        sum = 0
        if p_b > p_c:
            if a - b * 2 >= 0:
                a = a - b * 2
                sum += b * p_b
                if a - c * 2 >= 0:
                    sum += c * p_c
                else:
                    sum += a // 2 * p_c
            else:
                sum += a // 2 * p_b
        else:
            if a - c * 2 >= 0:
                a = a - c * 2
                sum += c * p_c
                if a - b * 2 >= 0:
                    sum += b * p_b
                else:
                    sum += a // 2 * p_b
            else:
                sum += a // 2 * p_c
        print(sum)


def throw_cub():
    n = int(input())
    for i in range(n):
        k = int(input())
        if k % 7 == 1:
            count = k // 7 + 1
        else:
            count = k // 7 + (k % 7 > 0)
        print(count)


def nasty_read_book():
    n = int(input())
    pages = list()
    for i in range(n):
        a, b = map(int, input().split(sep=' '))
        pages.append(a)
    current_page = int(input())
    for i in range(n - 1):
        if pages[i] <= current_page < pages[i + 1]:
            print(len(pages) - i)
            break
    else:
        print(1)


def Tokitsukaze_and_upgrade():
    n = int(input())
    residue = n % 4
    if residue == 0:
        print('1 A')
    elif residue == 1:
        print('0 A')
    elif residue == 2:
        print('1 B')
    else:
        print('2 A')


def make_triangle():
    a, b, c = map(int, input().split())
    if a + b > c:
        if a + c > b:
            if c + b > a:
                print(0)
            else:
                print(a - c - b + 1)
        else:
            print(b - a - c + 1)
    else:
        print(c - a - b + 1)


def phones_numbers():
    n = int(input())
    for i in range(n):
        count = int(input())
        number = input()
        if len(number) < 11:
            print('NO')
        else:
            if number.find('8', 0, len(number) - 10) > -1:
                print('YES')
            else:
                print('NO')


def even_lines():
    n = int(input())
    number = input()
    count = 0
    for i in range(n):
        if int(number[i]) % 2 == 0:
            count += i + 1
    print(count)
"""


def Petya_origami():
    n, k = map(int, input().split(sep=' '))
    r = 2
    g = 5
    b = 8
    count_blocknot = (n * r - 1) // k + 1 + (n * g - 1) // k + 1 + (n * b - 1) // k + 1
    print(count_blocknot)


Petya_origami()
