import java.io.*;
import java.util.*;

public class Main {
    static Stack<Integer> nums = new Stack<>();
    static Stack<Character> ops = new Stack<>();

    static void eval() {
        int b = nums.pop(), a = nums.pop();
        char c = ops.pop();
        int r = 0;
        if (c == '+') r = a + b;
        else if (c == '-') r = a - b;
        else if (c == '*') r = a * b;
        else if (c == '/') r = a / b;
        else r = (int) Math.pow(a, b);
        nums.push(r);
    }

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String str = br.readLine();
        if (str.charAt(0) == '-' || str.charAt(0) == '+') str = "0" + str;

        StringBuilder left = new StringBuilder();
        for (int i = 0; i < str.length(); i++) left.append('('); //先加左括号，变成合法前缀
        str = left.append(str).append(')').toString();  //加')'，可以计算最后一步结果

        char[] ch = str.toCharArray();
        int n = ch.length;

        for (int i = 0; i < n; i++) {
            char c = ch[i];
            if (Character.isDigit(c)) {
                int j = i, t = 0;
                while (Character.isDigit(ch[j])) t = t * 10 + (ch[j++] - '0');
                nums.push(t);
                i = j - 1;
            } else {
                if (c == ' ') continue;
                if (c == '(') ops.push(c);
                else if (c == ')') {
                    while (ops.peek() != '(') eval();
                    ops.pop();
                }
                else if (c == '+' || c == '-') {
                    if (c == '-' && i != 0 && !Character.isDigit(ch[i - 1]) && ch[i - 1] != ')') { 
                        if (ch[i + 1] == '(') {
                            nums.push(-1);
                            ops.push('*');
                        } else {
                            int j = i + 1, t = 0;
                            while (Character.isDigit(ch[j])) t = t * 10 + (ch[j++] - '0');
                            nums.push(-t);
                            i = j - 1;
                        }
                    } else { //由于+ -优先级最低，如果栈里有其他运算符，直接计算
                        while (ops.peek() != '(') eval();
                        ops.push(c);
                    }
                } else if (c == '*' || c == '/') {
                    while (ops.peek() == '*' || ops.peek() == '/' || ops.peek() == '^') eval();
                    ops.push(c);
                } else if (c == '^') {
                    while (ops.peek() == '^') eval();
                    ops.push(c);
                } else System.out.println("invalid operator!");
            }
        }
        System.out.println(nums.pop());
    }
}