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

}

/**************************************************************
	Problem: 1303
	User: mc002
	Language: C++
	Result: Wrong Answer
****************************************************************/