#include <bits/stdc++.h>
using namespace std;
int main(){
   float n,h;
   cin>>n;
   if (n>=500){
    h=n*0.8;
   }
       
   else if (n>=300){
    h=n*0.9;
   }  
   else {
   	h=n;
   }
   printf("%.2f",h);
}
/**************************************************************
	Problem: 1871
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:21 ms
	Memory:2072 kb
****************************************************************/