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

void main() {
  foreach (string line; stdin.lines) {
    double[] a = new double[10];
    double a1 = line.chomp.to!double;
    a[0] = a1;
    
    for (int i = 1; i <= 9; i++) {
      if (i % 2 != 0) {
        a[i] = a[i-1] * 2;
      } else {
        a[i] = a[i-1] / 3;
      }
    }

    writefln("%.8f", a.reduce!("a + b"));
  }
}