#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
	cin>>n;
	float s;
	if(n<10);{
	    s=n*2.2;
    } 
	else{
	     s=n*2;
    }
	printf("%.1f",s); 
return 0;
}

/**************************************************************
	Problem: 1303
	User: chenzelin
	Language: C++
	Result: Compile Error
****************************************************************/