#include<cstdio>
#include<iostream>
using namespace std;
int main(){
	double a;
	scanf("%lf",&a);
	double ans = a;
	for(int i = 2; i <= 10; i++){
		if(i%2==0){
			ans += a = a*2;
		}
		else{
			ans += a = a/3;
		}
	}
	printf("%.8lf\n",ans);
	return 0;
}