import java.util.ArrayDeque;
import java.util.Scanner;

import static java.lang.Integer.parseInt;

import java.util.*;

public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        String symbol;
        ArrayDeque<Integer> stack = new ArrayDeque<Integer>();

        while (sc.hasNext()) {
            symbol = sc.next();

            if (symbol.equals("+")) {
                stack.push(stack.pop() + stack.pop());
            } else if (symbol.equals("-")) {
                stack.push((stack.pop() * -1) + stack.pop());
            } else if (symbol.equals("*")) {
                stack.push(stack.pop() * stack.pop());
            } else {
                stack.push(Integer.parseInt(symbol));
            }
        }
        System.out.println(stack.pop());
    }
}

/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