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