#include<bits/stdc++.h>
using namespace std;
int x;
int main(){
	cin>>x;
		if(x>=30)  cout<<fixed<<setprecision(1)<<x*1.0;
		if(x>19&&x<30)  cout<<fixed<<setprecision(1)<<x*1.2;
		if(x<20&&x>9)  cout<<fixed<<setprecision(1)<<x*1.5;
		if(x<10)  cout<<fixed<<setprecision(1)<<x*1.80;
	return 0;
}
/**************************************************************
	Problem: 1304
	User: zhangziang
	Language: C++
	Result: Accepted
	Time:21 ms
	Memory:2072 kb
****************************************************************/