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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

//####################################################################
//#####In the Name Of Allah,the Most Gracious,the Most Merciful.######
//####################################################################

#include <bits/stdc++.h>
using namespace std;

#define maxn            100010
#define esp             1e-6
#define mod             1000000007
#define ll              long long


ll Q, H, S , D, N;

int main()
{
        cin >> Q >> H >> S >> D >> N;

        ll val1 = min(Q * 8, min(H * 4, min(S * 2, D)));
        ll val2 = min(Q * 4, min(H * 2, S));

        ll ans = 0;

        if(N >= 2){
                ll go = N / 2;
                ans += (go * val1);
                N -= (go * 2);
        }
        if(N == 1) ans += val2;

        cout << ans << endl;

        return 0;
}