#include<bits/stdc++.h>
using namespace std;
int main()
{
		int a;
	cin>>a;

	if(a>=10 ){
		cout<<a*2<<endl;
	} else{if(a<10 )
		cout<<a*2.2<<endl;
		
	}
	
	


return 0;
}

/**************************************************************
	Problem: 1303
	User: 1234512345
	Language: C++
	Result: Wrong Answer
****************************************************************/