#include <bits/stdc++.h>

#define loop(v, f, l) for(int v = (f), v##_ = (l); v < v##_; ++v)

using namespace std;

typedef long long int lint;
static inline int in(){ int x; scanf("%d", &x); return (x); }
static inline lint inl(){ lint x; scanf("lld", &x); return (x); }

double sequence(double a)
{
	double ans = a;
	loop(i, 2, 11)
	{
		if( i % 2 == 0 )
		{
			a *= 2;
			ans += a;
		}
		else
		{
			a /= 3;
			ans += a;
		}
	}
	return ans;
}

int main()
{
	double a;

	while( scanf("%lf", &a) != EOF )
	{
		printf("%lf\n", sequence( a ) );
	}

	return (0);
}