import java.util.Scanner;
import java.util.Stack;

public class Main {
	void run() {
		Scanner scan = new Scanner(System.in);
		Stack<Integer> stack = new Stack<Integer>();
		while (scan.hasNext()) {
			String token = scan.next();
			switch (token) {
			case "+": {
				int v1 = stack.pop();
				int v2 = stack.pop();
				stack.push(v2 + v1);
				break;
			}
			case "-": {
				int v1 = stack.pop();
				int v2 = stack.pop();
				stack.push(v2 - v1);
				break;
			}
			case "*": {
				int v1 = stack.pop();
				int v2 = stack.pop();
				stack.push(v2 * v1);
				break;
			}
			default: {
				stack.push(Integer.valueOf(token));
				break;
			}
			}
		}
		System.out.println(stack.pop());
	}
	public static void main(String[] args) {
		new Main().run();
	}
}


/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