import java.util.*;

public class Main {
  public static void main(String[] args) {
    try (Scanner sc = new Scanner(System.in)) {
      Deque<Integer> stack = new ArrayDeque<>();
      int tmpA = 0, tmpB = 0;
      String[] str = sc.nextLine().split("\\s");

      for (String s : str) {
        if (s.equals("+")) {
          tmpA = stack.pop();
          tmpB = stack.pop();
          stack.push(tmpA + tmpB);
        } else if (s.equals("-")) {
          tmpA = stack.pop();
          tmpB = stack.pop();
          stack.push(tmpB - tmpA);
        } else if (s.equals("*")) {
          tmpA = stack.pop();
          tmpB = stack.pop();
          stack.push(tmpA * tmpB);
        } else {
          stack.push(Integer.valueOf(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