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)

#!/usr/bin/env python3
import sys
sys.setrecursionlimit(10000000)
INF = 1<<32


def solve(Q: int, H: int, S: int, D: int, N: int):
    t = [
        [0.25, Q, Q],
        [0.50, H, H/2],
        [1, S, S/4],
        [2, D, D/8]
    ]

    # print(Q, H/2, S/4, D/8)

    t = sorted(t, key=lambda x:x[2])
    # print(t)

    nokori = N % t[0][0]
    ans = t[0][2]*4*(N-nokori)

    # print(ans, nokori)

    if nokori > 0:
        ans += t[1][2]*4
            
    print(int(ans))
    
    return



def main():
    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    Q = int(next(tokens))  # type: int
    H = int(next(tokens))  # type: int
    S = int(next(tokens))  # type: int
    D = int(next(tokens))  # type: int
    N = int(next(tokens))  # type: int
    solve(Q, H, S, D, N)

if __name__ == '__main__':
    main()