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();
            if(input.equals("+")) input = String.valueOf(Integer.parseInt(formula.poll())+Integer.parseInt(formula.poll()));
            else if(input.equals("-")) input = String.valueOf(-1*Integer.parseInt(formula.poll())+Integer.parseInt(formula.poll()));
            else if(input.equals("*")) input = String.valueOf(Integer.parseInt(formula.poll())*Integer.parseInt(formula.poll()));
            formula.push(input);
        }
        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