import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;

/** Simple calculator using reverse polish notation (RPN). */
public class RPNCalc {

   /** Stack for storing the operands. */
   private final Stack<Double> operands = new Stack<Double>();

   /** Evaluates an expression in RPN given as individual string tokens. */
   private void evaluate(String[] args) {
      for (int i = 0; i < args.length; ++i) {
         handleToken(args[i]);
      }

      if (operands.size() != 1) {
         System.err.println("Invalid expression!");
      }
      System.out.println(operands.pop());
   }

   /** Handles a single token. */
   private void handleToken(String token) {
      if (token.length() == 1 && operands.size() >= 2) {
         double op2 = operands.pop();
         double op1 = operands.pop();

         switch (token.charAt(0)) {
         case '+':
            operands.push(op1 + op2);
            return;
         case '-':
            operands.push(op1 - op2);
            return;
         case '*':
            operands.push(op1 * op2);
            return;
         case '/':
            operands.push(op1 / op2);
            return;
         }

         // no operation...
         operands.push(op1);
         operands.push(op2);
      }

      // must be number then
      try {
         operands.push(Double.parseDouble(token));
      } catch (NumberFormatException e) {
         throw new IllegalArgumentException("Invalid token: " + token);
      }
   }

   /** Main method. */
   public static void main(String[] args) throws IOException {
      BufferedReader reader = new BufferedReader(new InputStreamReader(
            System.in));
      String line = null;
      while ((line = reader.readLine()) != null) {
         try {
            new RPNCalc().evaluate(line.split(" +"));
         } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
         }
      }
   }
}