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

public class Main {

	public static void main(String[] args) {
		new Main().run();
	}

	void run() {
		Scanner sc = new Scanner(System.in);
		String line = sc.nextLine();
		String[] lineArr = line.split(" ");

		Deque<String> stack = new ArrayDeque<String>();
		for (String s : lineArr) {
			if ("+".equals(s)) {
				int a = Integer.parseInt(stack.pop());
				int b = Integer.parseInt(stack.pop());
				stack.push(String.valueOf(a + b));
			} else if ("-".equals(s)) {
				int a = Integer.parseInt(stack.pop());
				int b = Integer.parseInt(stack.pop());
				stack.push(String.valueOf(b - a));
			} else if ("*".equals(s)) {
				int a = Integer.parseInt(stack.pop());
				int b = Integer.parseInt(stack.pop());
				stack.push(String.valueOf(a * b));
			} else {
				stack.push(s);
			}
		}
		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