#include<bits/stdc++.h>
using namespace std;
int main(){
	int a;
	cin>>a;
	if(a>10){
		cout<<a*2;
	}else{
		cout<<a*2.2;
	}

	return 0;
}
/**************************************************************
	Problem: 1303
	User: zhenghaoxuan
	Language: C++
	Result: Wrong Answer
****************************************************************/