Problem:
Score : 300 points

Problem Statement

You've come to your favorite store Infinitesco to buy some ice tea.

The store sells ice tea in bottles of different volumes at different costs.
Specifically, a 0.25-liter bottle costs Q yen, a 0.5-liter bottle costs H yen, a 1-liter bottle costs S yen, and a 2-liter bottle costs D yen.
The store has an infinite supply of bottles of each type.

You want to buy exactly N liters of ice tea. How many yen do you have to spend?

Constraints

1 \leq Q, H, S, D \leq 10^8

1 \leq N \leq 10^9

All input values are integers.

Input

Input is given from Standard Input in the following format:

Q H S D
N

Output

Print the smallest number of yen you have to spend to buy exactly N liters of ice tea.

Sample Input 1

20 30 70 90
3

Sample Output 1

150

Buy one 2-liter bottle and two 0.5-liter bottles. You'll get 3 liters for 90 + 30 + 30 = 150 yen.

Sample Input 2

10000 1000 100 10
1

Sample Output 2

100

Even though a 2-liter bottle costs just 10 yen, you need only 1 liter.
Thus, you have to buy a 1-liter bottle for 100 yen.

Sample Input 3

10 100 1000 10000
1

Sample Output 3

40

Now it's better to buy four 0.25-liter bottles for 10 + 10 + 10 + 10 = 40 yen.

Sample Input 4

12345678 87654321 12345678 87654321
123456789

Sample Output 4

1524157763907942

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

# coding: utf-8
def get_ln_inputs():
    return input().split()


def get_ln_int_inputs():
    return list(map(int, get_ln_inputs()))


def main():
    prices = get_ln_int_inputs()
    N = get_ln_int_inputs()[0]
    M = N * 4

    result = [0, 0, 0, 0]

    prices_per_litre = [0, 0, 0, 0]
    for i in range(4):
        prices_per_litre[i] = prices[i] / (1 << i)
    
    price_rank = [sorted(prices_per_litre).index(price_per_l) for price_per_l in prices_per_litre]

    idx = 0
    if price_rank[idx] == 3:
        result[3] += M // 8
        M %= 8
        idx += 1
    
    cp = price_rank[idx]
    result[cp] += M // (1 << cp)

    print(sum(prices[i] * result[i] for i in range(4)))
    return


main()