AC

include <bits/stdc++.h>

using namespace std;

int main() {

double n, m, a, b, h, sum = 0;
cin >> n >> m >> a >> b >> h;
double x = a * b * h / 60000;
n = ceil(n);
m = ceil(m);
x = floor(x);
if (n <= 1.00) {
	sum = sum + 5.00;
} else if (n > 1.00) {
	sum = sum + 5.00 + (n - 1) * 0.50;
}
if (m <= 100) {
	sum = sum + 5.00;
} else if (m > 100) {
	sum = sum + 5.00 + (m - 100) * 0.15;
}
if (x <= 1) {
	sum = sum + 0.00;
} else if (x > 1) {
	sum = sum + (x - 1) * 1.0;
}
cout << fixed << setprecision(2) << sum;
return 0;

}