import java.io.*;
import java.util.*;

public class Main
{
    public static void main(String[] args)
    {
        Deque<String> formula = new ArrayDeque<String>();
        Scanner scan = new Scanner(System.in);

        while(scan.hasNext())
        {
            String input = scan.next();
            int num2,num1;
            switch(input)
            {
                case "+":
                    num2 = Integer.parseInt(formula.poll());
                    num1 = Integer.parseInt(formula.poll());
                    formula.push(String.valueOf(num1+num2));
                    break;
                case "-":
                    num2 = Integer.parseInt(formula.poll());
                    num1 = Integer.parseInt(formula.poll());
                    formula.push(String.valueOf(num1-num2));
                    break;
                case "*":
                    num2 = Integer.parseInt(formula.poll());
                    num1 = Integer.parseInt(formula.poll());
                    formula.push(String.valueOf(num1*num2));
                    break;
                default:
                    formula.push(input);
                    break;
            }
        }
        System.out.println(formula.poll());
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz