import std.stdio,std.string,std.conv;

int main()
{
	double a[10];
	string s;
	while((s = readln.chomp).length != 0)
	{
		double n = s.to!double;
		double ans = 0;
		a[0] = n;

		foreach(i;1..10)
		{
			if((i+1)%2 == 0)
			{
				a[i] = a[i-1]*2;
			}
			else
			{
				a[i] = a[i-1]/3;
			}
		}

		foreach(i;0..10)
		{
			ans += a[i];
		}

		writefln("%.8f",ans);
	}
	return 0;
}