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

public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String[] input = scan.nextLine().split(" ");

		Deque<Integer> stack = new ArrayDeque<Integer>();

		for(int i = 0; i < input.length; i++) {
			if(input[i].equals("+") || input[i].equals("-")
					|| input[i].equals("*") || input[i].equals("/")) {
				int b = stack.pop();
				int a = stack.pop();
				switch(input[i]) {
				case "+":
					stack.push(a + b);
					break;
				case "-":
					stack.push(a - b);
					break;
				case "*":
					stack.push(a * b);
					break;
				case "/":
					stack.push(a / b);
					break;
				}

			} else {
				stack.push(Integer.parseInt(input[i]));
			}
		}
		System.out.println(stack.pop());
		scan.close();
	}
}

/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