#include<bits/stdc++.h>
using namespace std;
int main(){
	int a;
	float b;
	cin>>a;
	if(a<=150){
		b=a*0.4463;
	}
		if(a>=151&&a<=400){
			b=b+150*0.4463+(a-150)*0.4663;
		}
		else{
			b=b+150*0.4463+(400-150)*0.4663+(a-400)*0.5663;
		}
    cout<<fixed<<setprecision(1)<<b;
    return 0; 
}