#include<iostream>
#include<cstdio>
using namespace std;

int main(){

	double a, sum;

	while(cin >> a){
		sum = a;
		for(int i=2; i<=10; i++){
			if(i % 2 == 0) a *= 2;
			else a /= 3;
			sum += a;
		}
		
		printf("%.8lf\n", sum);
	}

	return 0;

}