using System;
using System.Collections;
class RPN
{
   static void Main()
   {
      Stack s = new Stack();
      string line;
      while((line = Console.In.ReadLine()) != null)
      {
         foreach(string a in line.Split(new char[] {' '}))
         {
            if(a.Length == 0)
               continue;
            try{ s.Push(Double.Parse(a) + ""); }
            catch (Exception e)
            {
               try
               {
                  double d2 = Double.Parse((string)s.Pop());
                  double d1 = Double.Parse((string)s.Pop());
                  switch (a)
                  {
                     case "+": s.Push(d1 + d2 + ""); break;
                     case "-": s.Push(d1 - d2 + ""); break;
                     case "*": s.Push(d1 * d2 + ""); break;
                     case "/": s.Push(d1 / d2 + ""); break;
                     default: Console.WriteLine("unknown operator: " + a);
                        break;
                  }
               }
               catch (Exception e2) { Console.WriteLine("stack underflow"); }
            }
         }
         Console.WriteLine(s.Count != 0 ? s.Peek() : "<empty>");
      }
   }
}