#include<iostream>
#include <iomanip>
using namespace std;
int main(){
    int a;
    double fee;
    cin>>a;
    if(a<=150){
        fee=a*0.4463;
    }
    else if(a>150&&a<=400){
        fee=0.4463*150+(a-150)*0.4663;
    }
    else{
        fee=0.4463*150+250*0.4663+(a-400)*0.5663;
    }
    cout << fixed << setprecision(1) << fee << endl;
    return 0;
}