include
using namespace std;
int main() {
int n;
cin >> n;
double a, b, c ;
if (n <= 150) {
a = n * 0.4463;
printf("%.1lf", a);
}
if (n >= 151 && n <= 400) {
b = (n - 150) * 0.4663 + 150 * 0.4463;
printf("%.1lf", b);
}
if (n >= 401) {
c = 150 * 0.4463 + 250 * 0.4663 + (n - 400) * 0.5663;
printf("%.1lf", c);
}
return 0;
}
