num = int(input())
price = 0.0
if num<=150:
    price += num*0.4463
else:
    price += 150*0.4463 # 小于150的部分
    num -= 150
    if num<=250:
        price += num*0.4663
    else:
        price += 250*0.4663
        num -= 250
        price += num*0.5663
print(f"{price:.1f}")

#include<bits/stdc++.h>
using namespace std;
int main(){
    double e,money=0;
    cin>>e;
    if(e<=150)	
        money=e*0.4463;
    if(e>150||e==400)	
        money=150*0.4463+(e-150)*0.4663;
    if(e>400)		
        money=150*0.4463+250*0.4663+(e-400)*0.5663;
    printf("%.1lf\n",money);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	if(n<=150)cout<<fixed<<setprecision(1)<<n*0.4463;
	else if(n>=150&&n<=400)cout<<fixed<<setprecision(1)<<150*0.4463+(n-150)*0.4663;
	else cout<<fixed<<setprecision(1)<<150*0.4463+250*0.4663+(n-400)*0.5663;
	return 0;
}