#include <iostream>
using namespace std;

int main()
{
    long long x;
    cin >> x;
    if (x <= 150) 
    {
        cout << int(x * 0.4463 * 10) / 10.0;
        return 0;
    }
    if (x <= 400) 
    {
        cout << int(x * 0.4663 * 10) / 10.0;
        return 0;
    }
    cout << int(x * 0.5663 * 10) / 10.0;
    return 0;
}