#include<iostream>
using namespace std;
int main()
{
	double sum,s,p;
	while((cin>>s)!=0){
		sum=s;
		p=s*100000000;
		for(int i=1;i<10;i++){
			if(i%2==1)s=s*2;
			if(i%2==0)s=s/3;
			sum=sum+s;
		}
		cout<<int(sum)<<'.';
		sum=p;
		for(int i=1;i<10;i++){
			if(i%2==1)p=p*2;
			if(i%2==0)p=p/3;
			sum=sum+p;
			while(sum>100000000)sum=sum-100000000;
		}
		if(int(sum)%10>5)cout<<int(sum)+1<<endl;
		else cout<<int(sum)<<endl;
	}
	return 0;
}