import exercise.*;
import java.util.Scanner;
import java.util.Stack;

public class RPN {
    public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);

    Stack<Rational> stack = new Stack<Rational>();

        while (scanner.hasNext()) {
            String s = scanner.next();
         if      (s == "+") stack.push(Rational.addition(stack.pop(),stack.pop()));
        else if (s == "*") stack.push(Rational.multiplikation(stack.pop(),stack.pop()));
    else if (s.== "/") stack.push(Rational.division(stack.pop(),stack.pop()));
    else if (s == "-") stack.push(Rational.subtraktion(stack.pop(),stack.pop()));
        else stack.push(new Rational(Long.parseLong(s)));
        }
        System.out.println(stack.pop());

    }
}