Напитки из Черноголовки

a, b, c, d = tuple(map(lambda x: int(x), input().split()))
n = float(input())
summa = 0
liters = 0
while liters != n:
    if 2 * c > d and 4 * b > d and 8 * a > d and liters + 2 <= n:
        summa += d
        liters += 2
    elif liters + 1 <= n and 2 * b > c and 4 * a > c:
        summa += c
        liters += 1
    elif liters + 0.5 <= n and 2 * a > b:
        summa += b
        liters += 0.5
    else:
        summa += a
        liters += 0.25
print(summa)

a, b, c, d = map(int, input().split())
n = float(input())
 
p = [a]
p.append(2 * a if 2 * a < b else b)
p.append(2 * b if 2 * b < c else c)
p.append(2 * c if 2 * c < d else d)
 
res = 0
while n:
    if n >= 2:
        res += p[3]
        n -= 2
        continue
    if n >= 1:
        res += p[2]
        n -= 1
        continue
    if n >= 0.5:
        res += p[1]
        n -= 0.5
        continue
    res += p[0]
    n -= 0.25
        
print(res)

#a, b, c, d = tuple(map(lambda x: int(x), input().split()))
#n = float(input())
a = [18, 30, 70, 100]
n = 3
summa = 0
liters = 0
lim = [
       {'vol' : 0.25, 'cost' : 18, 'price' : 0},
       {'vol' : 0.5, 'cost' : 30, 'price' : 0},
       {'vol' : 1, 'cost' : 70, 'price' : 0},
       {'vol' : 2, 'cost' : 100, 'price' : 0}]
for i in range(0, len(lim)):
    lim[i]['cost'] = a[i]
    lim[i]['price'] = lim[i]['cost']/lim[i]['vol']
lim.sort(key=lambda x: x['price'])
i = 0
while liters<n:
    if lim[i]['vol']<=(n-liters):
        liters += lim[i]['vol']
        summa += lim[i]['cost']
    else:
        i += 1
print(liters, summa)

x = min(4 * a, 2 * b, c)
print(n % 2 * x + n // 2 * min(2 * x, d))

def foo1 (a, b, c, d, n):
    a = [a,b,c,d]
    summa = 0
    liters = 0
    lim = [
           {'vol' : 0.25, 'cost' : 18, 'price' : 0},
           {'vol' : 0.5, 'cost' : 30, 'price' : 0},
           {'vol' : 1, 'cost' : 70, 'price' : 0},
           {'vol' : 2, 'cost' : 100, 'price' : 0}]
    for i in range(0, len(lim)):
        lim[i]['cost'] = a[i]
        lim[i]['price'] = lim[i]['cost']/lim[i]['vol']
    lim.sort(key=lambda x: x['price'])
    i = 0
    while liters<n:
        if lim[i]['vol']<=(n-liters):
            liters += lim[i]['vol']
            summa += lim[i]['cost']
        else:
            i += 1
    return summa
 
def foo2 (a, b, c, d, n):
    x = min(4 * a, 2 * b, c)
    return n % 2 * x + n // 2 * min(2 * x, d)
 
from random import randint
total, counter = 1000, 0
for _ in range(total):
    a,b,c,d = tuple([randint(1, 10**5) for _ in range(4)])
    n = randint(1, 10**5)
    if foo1 (a, b, c, d, n) == foo2 (a, b, c, d, n):
        counter += 1
print(total, counter)
 
#1000 1000