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

int main(){
	double s[10], sum;
	while(cin >> s[0]){
		for(int i = 1; i < 10; i++){
			if(i%2 == 1) s[i] = s[i-1] * 2;
			else s[i] = s[i-1] / 3;
		}

		for(int i = 0; i < 10; i++){
			sum += s[i];
		}
		printf("%.8lf\n", sum);
	}
}