#include<bits/stdc++.h>
using namespace std;
long long n,a[10001],maxn;
double s;
int main(){
	cin>>n;
	if(n<=150)
	{
		s+=n*0.4463;
	}
	else
	{
		s+=150*0.4463;
		if(n<=400)
		{
			s+=(n-150)*0.4663;
		}
		else
		{
			s+=(n-400)*0.5663;
		}
	}
	printf("%0.1d",s);
    return 0;
}