package com.nowcoder.huawei;

import java.util.*;

public class LISP {

    // 只通过80%

    // (+ (* 2 3) (^ 4))

    // (+ (* 2 3) (^ 4))(2 3)

    // ((+ 2 3)

    // ((+ 2 3))

    // (^ (+ (* 2 3) (^ ((^ 4)))))

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        String express = scanner.nextLine();

        Stack<Character> stack = new Stack<>();

        for (int i = 0; i < express.length(); i++) {

            char c = express.charAt(i);

            if (c == ')') {

                StringBuilder builder = new StringBuilder();

                char top;

                while (!stack.empty() &&(top = stack.pop()) != '(') {

                    builder.append(top);

                }

                String currExp = builder.reverse().toString();

//                System.out.println(currExp);

                String[] ops = currExp.split(" ");

                if (ops.length == 2) {

                    int value = Integer.valueOf(ops[1]);

                    value++;

                    String count = String.valueOf(value);

                    for (int j = 0; j < count.length(); j++) {

                        stack.push(count.charAt(j));

                    }

                } else if (ops.length == 3) {

                    int a = Integer.valueOf(ops[1]);

                    int b = Integer.valueOf(ops[2]);

                    int value = 0;

                    switch (ops[0]) {

                        case "+":

                            value = a + b;

                            break;

                        case "*":

                            value = a * b;

                            break;

                    }

                    String count = String.valueOf(value);

                    for (int j = 0; j < count.length(); j++) {

                        stack.push(count.charAt(j));

                    }

                } else if (ops.length == 1) {

                    for (int j = 0; j < ops[0].length(); j++) {

                        stack.push(ops[0].charAt(j));

                    }

                }

            } else {

                stack.push(c);

            }

        }

        StringBuilder builder = new StringBuilder();

        while (!stack.empty())

            builder.append(stack.pop());

        try {

            System.out.println(Integer.valueOf(builder.reverse().toString()));

        } catch (Exception e) {

            System.out.println(-1);

        }

    }

}