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



void main() {
    string input;

    while ((input = readln.chomp).length != 0) {
        double sum = 0;
        double[] data = new double[](10);

        data[0] = input.to!double;
        foreach (i; 1..10) {
            if ((i % 2) == 0) {
                /* 偶数項 */
                data[i] = data[i - 1] / 3;
            } else {
                /* 奇数項 */
                data[i] = data[i - 1] * 2;
            }
        }

        foreach (i; 0..10) {
            sum += data[i];
        }

        writefln("%.8f", sum);
    }
}