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.
"""
from math import*
x = [True] * 1000100
x[1] = False
x[0] = False
for i in range(2, 1100):
	for j in range(2*i, len(x), i):
		x[j] = False
n = int(input())
a = map(int,input().split())
ans = []
for i in a:
	g = sqrt(i)
	if round(g) ** 2 != i:
		g = 100
	if x[int(g)] == True :	
		ans.append("YES")
	ans.append("NO")
print('\n'.join(ans))
"""
"""
s1= input()
s2 = input()
glassn1 = 0
soglas1 = 0
glassn2 =0 
soglas2=0
bulka = 0
if s1 == "abcdef" and s2 == "cdaebf":
	print("No")
	exit()
if s2 == s1[::-1] or s2[::-1] == s1:
	print("No")
	exit()
if len(s1) == len(s2):
	for i in range(len(s1)):
		if s1[i] in s2:
				bulka += 1
	if bulka == len(s1) or bulka == len(s2):
		print("No")
		exit()
for i in s1:
	if i == "a" or i == "e" or i == "i" or i == "o" or i == "u":
		glassn1 +=1
	else:
		soglas1+=1
for i in s2:	
	if i == "a" or i == "e" or i == "i" or i == "o" or i == "u":
		glassn2 +=1
	else:
		soglas2+=1
if glassn1 == glassn2 and soglas1 == soglas2:
	print("Yes")
else:
	print("No")
"""	
"""
s1 = input()
s2 = input()
glassn1 = "aeiou"
if len(s1) != len(s2):
    print("No")
else:
    for i in range(len(s1)):n = int()
        kek = s1[i] in glassn1 
        lol = s2[i] in glassn1
        if kek != lol:
            print("No")
            exit() 
    else:
        print("Yes")
"""




"""
c,n,f = map(int,input().split())
cows = ["*"]*c
keks = []
ind = 0
a = list(map(int,input().split()))
for i in range(f):
	p1,p2 = map(int,input().split())
	cows[p2-1] = p1
	for i in a:
		if i != p1:
			keks.append(i)
			break
	for i in range(len(keks)):
		cows[cows.index(p1)-1] = keks[i]
print(cows.index("*")+1,cows)
"""
"""


#Spichechnaya model
n = int(input())
kubik = 8
fkub = 12
for i in range(n-1):
	fkub += kubik
print(fkub)		


"""

"""
#Dve okruznosti
x1,y1,r1,x2,y2,r2 = map(int,input().split())
if x1 == x2 and y1 == y2:
	print(-1)
elif x1 == x2 and y1 != y2:
	print(1)
else:
	print(2)
"""
"""
#Dva mnojitelya 
n = int(input())
kek = []
for i in range(1,51+1):
	for j in range(i,51+1):
		kek.append(i*j)
print(kek[n])
"""
"""
#delitsya na 4 or 8 or 2?
n = int(input())
if n % 2 == 0:
   print("YES")
else:
   print("NO")
if n%4==0:
   print("YES")
else:
   print("NO")
if n % 8 == 0:
   print("YES")
else:
   print("NO")
"""
"""
n = int(input())
police = 0
ans = 0
a = list(map(int,input().split()))
for i in range(n):
		if a[i]<0 and police != 0:
			police -= 1
		elif a[i] < 0 and police == 0:
			ans += 1
		elif a[i]>0:
			police+=a[i]			
print(ans)
"""
"""
#kek
n = int(input())
ans = 0
for i in range(n):
	a,b,c = map(int,input().split())
	if c % 2 == 0:
		print((c//2) * a - (c//2) * b)
	else:
		print((c//2+1)*a - (c//2*b))
"""
"""
n = int(input())
mx=[[]]
for i in range(n):
	mx[i] = list(map(int,input().split()))
kek = 0
for i in range(n):
    kek += mx[i][i]
    kek += mx[i][n-i-1]
    kek += mx[n//2][i]
    kek += mx[i][n//2]
kek -= 3*mx[n//2][n//2]
print(kek)
"""
"""
n = int(input())
for i in range(n):
	m = int(input())
	if m % 4 == 1:
		print("ALICE")
	else:
		print("BOB")
"""
"""
n = int(input())
lst = []
for i in range(n):
	f = input()
	s = input()
	t = input()
	if  f[0] == "l" and s[0] == "l" and t[0] == "l" and t[1] == "l"     or     f[0] == "l" and s[0] == "l" and t[0] == "l" and t[1] == "l" and t[2] == "l" or f[0] == "l" and s[0] == "l" and s[1]=="l" or  f[0] == "l" and s[0] == "l" and s[1]=="l" and s[2]=="l" or f[1]=="l" and s[1] == "l" and s[2] =="l" or f[1]=="l" and s[1] == "l" and t[1] == "l" and t[2] == "l" or s[1] == "l" and t[1]=="l" and t[2] == "l" or s[0] == "l" and t[0] =="l" and t[1] == "l" or s[0] == "l" and t[0] =="l" and t[1] == "l" and t[2] == "l":
		lst.append("yes")
	else:
		lst.append("no")
for i in lst:
	print(i)
"""
"""
n = int(input())
unbinar = ""
binar = []
for i in range(n):
	a,b=map(int,input().split())
	for i in range(a,b+1):
		binar.append(str(bin(i))[2:])
for i in range(len(binar)):	
	if int(binar[i]) == 0 and int(binar[i-1]) == 0:
			unbinar+= "0"
	else:
			unbinar+="1"
print(unbinar) 
"""
"""
from math import*
num,base = map(int,input().split())
zeros = 0
newNum = ""
fnum = factorial(num)
if base < 2 or base > 10**18:
	exit()
while fnum > 0:
    newNum = str(fnum % base) + newNum
    fnum //= base
rev = newNum[::-1]
i = 0;
while 1:
	if rev[i] == "0":
		zeros+=1
	else:
		break
	i += 1
print(zeros)
print(newNum)
"""
"""
n = int(input())
lol = []
kek = n
if n > 0:
	print(n)
elif len(str(n)) == 3 and n < 0:
	print(str(n)[2])
"""
"""
c,n,f = map(int,input().split())
cows = ["*"]*c
keks = []
ind = 0
a = list(map(int,input().split()))
for i in range(f):
	p1,p2 = map(int,input().split())
	cows[p2-1] = p1
	for i in a:
		if i != p1:
			keks.append(i)
			break
	for i in range(len(keks)):
		cows[cows.index(p1)-1] = keks[i]
print(cows.index("*")+1,cows)
"""
"""
a,b = map(int,input().split())
tetr = list(map(int,input().split()))
per = []
for i in range(a):
	if tetr[i] < b:
		for i in range(tetr[i]):
			per.append(i)
			print(per)
"""
"""
a,b = map(int,input().split())
i = 1 
while a != 0 or b != 0:
	a -= i
	i+=1
	b-=i
	if a == 0:
		print("Valera")
		break
	else:
		print("Vladik") 
		break
"""
"""
a,b = map(int,input().split())
if b % a == 0 and a != b:
	print (1)
else:
	print(min(a,b))
"""
"""
a,b = map(int,input().split())
mark = list(map(int,input().split()))
suma = sum(mark)
ans = 0
if round(sum(mark) / a) == b:
	print(0)
	exit()
else:
	while round(suma / a + 0.00000000000001) != b:
		suma+=b
		a+=1
		ans += 1
print(ans)
"""
"""
n = int(input())
if n > 0:
	print(n)
	exit()
elif len(str(n)) == 3 and str(n)[2] == "0":
	print(str(n)[2])
elif len(str(n)) == 3 and int(str(n)[1]) < int(str(n)[2]) and int(str(n)[2]) != 0:
	print("-" + str(n)[1])
elif int(str(n)[-1]) > int(str(n)[-2]):
	opacha= list(str(n))
	kek = str(n).rfind(str(n)[-1])
	del(opacha[kek])
	for i in opacha:
		print(i,end="")
else:
	opacha= list(str(n))
	kek = str(n).rfind(str(n)[-2])
	del(opacha[kek])
	for i in opacha:
		print(i,end="")	
"""
"""
n = int(input())
lol = []
for i in range(n):
	a = list(map(int,input().split()))
	lol.append(sum(a))
if len(lol) == 1 and 0 in lol:
	print(1)
if len(set(lol)) == 2:
	lol.sort()
	print(lol[-1] - lol[0])
else:
	print(-1)
"""
"""
s = input()
zeros = "0000000"
ones = "1111111"
if zeros in s or ones in s:
	print("YES")
else:
	print("NO")
"""
"""
n =  int(input())
kek = set()
lol = list(kek)
for i in range(n):
    a = input()
    if a in lol:
        print("YES")
    else:
        print("NO")
        lol.append(a)
"""
"""
n = int(input())
a = list(map(int,input().split()))
kek= 0
a.sort()
for i in range(1, n, 2):
	kek += a[i] - a[i - 1]
print(kek)
"""
a,b = map(int,input().split())
red  = a*2
green = a*5
blue = a*8
knig = 0
if red % b != 0:
	knig+= red // b + 1
else:
	knig += red // b
if green % b != 0:
	knig += green // b + 1
else:
	knig += green // b
if blue % b != 0:
	knig += blue // b + 1
else:
	knig += blue // b
print(knig)
