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 JavaScript (Node.js 12.16.1) (judge verdict: Accepted)

process.stdin.resume();
process.stdin.setEncoding('utf8');

var lines = [];
var reader = require('readline').createInterface({
  input: process.stdin,
  output: process.stdout
});
reader.on('line', (line) => {
  lines.push(line);
});
reader.on('close', () => {
    const [Q, H, S, D] = lines[0].split(" ").map(v=>BigInt(v));
    const N = BigInt(lines[1]);
    if(N%2n==0n){
        const unit = min(Q*8n, H*4n, S*2n, D);
        log(N/2n*unit);
    }else{
        const unit1 = min(Q*4n, H*2n, S);
        const unit2 = D;
        if(unit1*2n < D){
            log(N*unit1);
        }else{
            log((N-1n)/2n * unit2 + unit1);
        }
    }
});

min = (...a) => {return a.reduce((a,b)=>a<b?a:b, a[0])}
log = (a)=>{console.log(a.toString())};