#include<bits/stdc++.h>
using namespace std;
int main(){
	int a;
	float b;
	cin>>a;
	if(a<10) b=a*2.2;
	if(a>=10) b=a*2;
	printf("%.1f",b);
}
/**************************************************************
	Problem: 1641
	User: toughuatao1
	Language: C++
	Result: Wrong Answer
****************************************************************/