#include	<iostream>
#include	<cstdio>

using namespace std;

int main(void) {
	while(1) {
		double seq[10] = { 0.0 };
		double sum = 0;
		cin >> seq[0];
		
		if( cin.eof() )		break;
		sum += seq[0];
		for(int i = 1; i < 10; i++) {
			if(i % 2 == 1) {
				seq[i] = seq[i - 1] * 2;
			} else {
				seq[i] = seq[i - 1] / 3;
			}
			sum += seq[i];
		}
		printf("%.8f\n", sum);
	}
	
	return 0;
}