import std.stdio;
import std.algorithm;
import std.string;
import std.conv;
import std.math;

void main(){

    while(true){
	auto s = readln();
	if(stdin.eof()) break;
	real n = to!real(chomp(s));
	real sum=0;
	for(int i=0;i<10;i++){
	    sum += n;
	    if(i%2==0)	n *= 2;
	    else n /= 3;
	}
	writef("%.6f\n",sum);
    }
}