import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayDeque;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;

public class Main {

	public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] stringArray = br.readLine().split("\\s");

		Stack<Integer> que = new Stack<Integer>();
		int a = 0;
		int b = 0;
		for (int i = 0; i < stringArray.length; i++) {
			if (stringArray[i].equals("+")) {
				a = que.pop();
				b = que.pop();
				que.add(b + a);
				continue;
			}
			if (stringArray[i].equals("-")) {
				a = que.pop();
				b = que.pop();
				que.add(b - a);
				continue;
			}
			if (stringArray[i].equals("*")) {
				a = que.pop();
				b = que.pop();
				que.add(b * a);
				continue;
			}
			if (stringArray[i].equals("/")) {
				a = que.pop();
				b = que.pop();
				que.add(b + a);
				continue;
			}
			que.push(Integer.parseInt(stringArray[i]));
		}
		System.out.println(que.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