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);
}
}
}