#include<bits/stdc++.h>
using namespace std;
int main(){
	float a,k;
	cin>>a;
	if(a>=500){
		k=a*0.8;
	}
	if(a<=500&&a>=300){
		k=a*0.9;
	}
	if(a<300){
		k=a;
	}printf("%.2f",k);
}
/**************************************************************
	Problem: 1871
	User: tonghuawei
	Language: C++
	Result: Wrong Answer
****************************************************************/