#include<iostream>
#include<iomanip>

using namespace std;

int main() {
	
	double n[10] = {};
	
	while(cin >> n[0]) {
	
	double sum = n[0];
	
	for(int i=1;i<10;i++) {
		
		if(i % 2)
			n[i] = n[i-1] * 2;
		
		else
			n[i] = n[i-1] / 3;
			
		sum += n[i];
		
	}
	
	cout << fixed << setprecision (8)<< sum << "\n";
	
}
	
	return 0;
}

