#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	cin>>n;
	if(n>=30){
		cout<<n*1;
	}else{
		if(20<=n<=29){
			cout<<n*1.2;
		}else{
			if(10<=n<=19){
				cout<<n*1.5;
			}else{
				if(n<10){
					cout<<n*1.8;
				}
			}
		}
	}
	return 0;
}
/**************************************************************
	Problem: 1304
	User: linyuhang
	Language: C++
	Result: Wrong Answer
****************************************************************/